JavaBasicProblemSolving
Java Tutorial
java holo high level programming language. Eta develop kore sun micro system but currently own by oracle.
- Platform independent language.(WORA) – write once run anyway- all operating system code to be supported any place just like java independent.
real life er sathe object gulo mil reke amara programming korbo.
-
Java supported web based application.
-
Robust language : - that means eti akti strong and sequence language. Erroe handling ba exception handling er flexible ase.
-
Secure programming language.
-
Multi-threading programming:- language. Akoi sathe onek gulo kaj kora jai. Say music, game, any pdf open seta backend a rakha jai. Say 20 liner code asi sekhan theke 100 liner code a jump korte pare.
-
Draw:- c/c++ Jodi kono windows operating system a ami run kore thaki tahole se run korbe kintuo oi akoi programming niye Jodi ami c/c++ code linux a run kore thaki tahole kintuo run korbena.
-
But java all operating system a supported e jonno java ke amara platform independent language bole thaki. Java virtual machine er karone java platform language. JVM
-
Java Run :-
-
Fast java code . dile extension thake.
-
Java code ti compiler er maddhome akta byte code a convert kore jvm a niye ase. Jar jonno windows, lenux, Mac sokol operating a run korte pare.
-
History of java:
-
Required software:
#jdk – java development kids #ide – Integreated development enviornment eclipse/netbeans/inteli j idea. -
Java version : -
-
Java Diagram:-
Tutorial: 1 Completed learn
-
Project under– package uder– class.
-
Package / class name always start to capital letter.
-
Java program a akta user defined class thakbe.
#3rd class name
Create class :-
Exm: public class pro {
}
- Java starting point thakbe jekhan theke program execute hoy ba run hoy. Program compile korte pare. Just like call main method .
Create method: - Ex: public static void main(String args[]) {
}
Public – acces modifier Static – java keyword , fixed ase Void – kono kisu return korbe Main – main method () first bracket thakle setake method hisabe sinbo.
-
Java keyword bola hoye thake. Jamon public , static void , main.
-
Create to java program Display:
System.out.println(“ “ ); Etake statement o bola hoy statement er sese semiclone dite hoy.
-
Println(“Java”); - print korar somoy akta line print kore thake.
-
Print(“java”); - print korar somoy kono line, print kore thakena. Akoi line a print hoy.
Tutorial: 2 Completed learn
The End of part First java app#
What is Escape sequence :- Eta akta special character jeta thakbe backslash sinno er pore , etake escape sequence ba backslash char o bola hoy.
\ - backslash
\b – backspace – sei num/word muse jabe.
\t – tab – 4 ghor porjonto faka nibe.
\n – newline
\r – carriage return – samne ja thakbe clear hoye jabe like – about\r dile about thakbena.
\ “ – double quote- double quote hobe – “u”
\’ – single quote – ‘u’
\\ – backslash - uzz\\al - output uzz\al
\t - Inserts a tab in the text at this point. \b - Inserts a backspace in the text at this point. \n - Inserts a newline in the text at this point. \r - Inserts a carriage return in the text at this point. \f - Inserts a form feed in the text at this point. ' - Inserts a single quote character in the text at this point. " - Inserts a double quote character in the text at this point. \ - Inserts a backslash character in the text at this point.
package Feburary;
public class FastIntro {
public static void main( String args[]){
// tab
System.out.println("1 \t5");
//break
System.out.println("Banglade\bsh is our homeland");
System.out.println("This is my Techoners\n is our pleasure");
System.out.println("Bangla\rdesh is our");
System.out.println("Bangla\fdesh is our ");
System.out.println("I will give mo\'re thing's
Techoners");
System.out.println(" \"Java programming language\"
");
System.out.println("Teconer is my fa\\st Job career");
} }
The best article..:---
System.out.println(""Uzzal" Mon\dal\n Android learner \t 0198\b045\r0700");
Java Execution Start / Java phases Tutorial num – 04
- Eropr java compiler thkeke byte code a jai
- Java virtual machine thke program ta excute hoy
The End of part Java Phases Tutorial
Varibale and DataType In Java
Varibale and Data Type
Variable - 1.if any data storage to including value, this call variable. num1- variable , 20 is value
- Variable write to rules:
- Variable write to rules:
Variable name digit / math don’t start to decleare. keyword function/method name don’t start to decleare.
- Variable delceration syantax:
• Fast dattype • Second variable. • int a = 10;
• - int datatype , a variable – 10 value.
Data type 02 prokar.
Numeric, Integral. Integral- character char, Integral. Integer – byte, short, Int, long. Floating point – float , double.
Compiler blog
package FeburaryJAVA;
public class SecondJava {
public static void main(String args[]) { int num = 10;
float point = (float) 10.25; double result = 100.20; boolean go = true;
// variable declear, variable intilize korbo. char c; char ca = 'a'; //dynamic initlize.
int i; double d; float f; short s; byte b=127; boolean b1; long l;
/*byte variable: 8 bit, min -128, max 127, default 0; */
byte by = 127; byte byt = -128;
System.out.println("Byte = "+by);
System.out.println("Byte = "+byt);
/*short variable 16 bit,# max 32,768 # min -32767
*/ short sh = 32767; short sho = -32768; System.out.println("short "+sh); System.out.println("short "+sho);
/*Int variable 32 bit - #max 2147483647 #min -
2147483648*/ int i1 = 2147483647; int i2 = -2147483648; System.out.println("Int : "+i1); System.out.println("Int : "+i2);
/* long 64 bit #max9,223,372,036,854,775,807 min -9,223,372,036,854,775,808(-2^63)
*/
/**/
long lo = 1000L; long lon = 2000L;
System.out.println("Long varibale "+lo);
System.out.println("Long varibale "+lon);
/*float 32 bit. 754 floating point
* float f1 = 10.25f*/ float folat = 10.25f;
System.out.println("Float : "+folat);
/*double 64bit, 754 floating point*/
double db = 120.45;
System.out.println("Double value is a "+db);
/*boolean return to true and false.*/
boolean one = false;
System.out.println("Boolean value is a : "+one);
/*character is a 16 bit */
char ch = 'a';
System.out.println("Character : "+ch);
}
}
-
Variables are nothing but reserved memory locations to store values. This means that when you create a variable you reserve some space in the memory.
-
Based on the data type of a variable, the operating system allocates memory and decides what can be stored in the reserved memory. Therefore, by assigning different data types to variables, you can store integers, decimals, or characters in these variables.
• Primitive Data Types • Reference/Object Data Types
There are eight primitive datatypes supported by Java. Primitive datatypes are predefined by the language and named by a keyword. Let us now look into the eight primitive data types in detail.
• Byte data type is an 8-bit signed two's complement integer
• Minimum value is -128 (-2^7)
• Maximum value is 127 (inclusive)(2^7 -1)
• Default value is 0
• Byte data type is used to save space in large arrays, mainly in place of integers, since a byte is four times smaller than an integer.
• Example: byte a = 100, byte b = -50
• Short data type is a 16-bit signed two's complement integer • Minimum value is -32,768 (-2^15) • Maximum value is 32,767 (inclusive) (2^15 -1) • Short data type can also be used to save memory as byte data type. A short is 2 times smaller than an integer • Default value is 0. • Example: short s = 10000, short r = -20000 int • Int data type is a 32-bit signed two's complement integer. • Minimum value is - 2,147,483,648 (-2^31) • Maximum value is 2,147,483,647(inclusive) (2^31 -1) • Integer is generally used as the default data type for integral values unless there is a concern about memory. • The default value is 0 • Example: int a = 100000, int b = -200000
• Long data type is a 64-bit signed two's complement integer • Minimum value is -9,223,372,036,854,775,808(-2^63) • Maximum value is 9,223,372,036,854,775,807 (inclusive)(2^63 -1) • This type is used when a wider range than int is needed • Default value is 0L • Example: long a = 100000L, long b = -200000L float • Float data type is a single-precision 32-bit IEEE 754 floating point • Float is mainly used to save memory in large arrays of floating point numbers • Default value is 0.0f • Float data type is never used for precise values such as currency • Example: float f1 = 234.5f
• double data type is a double-precision 64-bit IEEE 754 floating point • This data type is generally used as the default data type for decimal values, generally the default choice • Double data type should never be used for precise values such as currency • Default value is 0.0d • Example: double d1 = 123.4
• boolean data type represents one bit of information • There are only two possible values: true and false • This data type is used for simple flags that track true/false conditions • Default value is false • Example: boolean one = true
• char data type is a single 16-bit Unicode character • Minimum value is '\u0000' (or 0) • Maximum value is '\uffff' (or 65,535 inclusive) • Char data type is used to store any character • Example: char letterA = 'A'
• Reference variables are created using defined constructors of the classes. They are used to access objects. These variables are declared to be of a specific type that cannot be changed. For example, Employee, Puppy, etc. • Class objects and various type of array variables come under reference datatype. • Default value of any reference variable is null. • A reference variable can be used to refer any object of the declared type or any compatible type. • Example: Animal animal = new Animal("giraffe");
A literal is a source code representation of a fixed value. They are represented directly in the code without any computation. Literals can be assigned to any primitive type variable. For example − byte a = 68; char a = 'A'; byte, int, long, and short can be expressed in decimal(base 10), hexadecimal(base 16) or octal(base 8) number systems as well. Prefix 0 is used to indicate octal, and prefix 0x indicates hexadecimal when using these number systems for literals. For example − int decimal = 100; int octal = 0144; int hexa = 0x64; String literals in Java are specified like they are in most other languages by enclosing a sequence of characters between a pair of double quotes. Examples of string literals are − Example "Hello World" "two\nlines" ""This is in quotes"" String and char types of literals can contain any Unicode characters. For example − char a = '\u0001'; String a = "\u0001";
Java language supports few special escape sequences for String and char literals as well. They are −
Notation Character represented \n Newline (0x0a) \r Carriage return (0x0d) \f Formfeed (0x0c) \b Backspace (0x08) \s Space (0x20) \t tab " Double quote ' Single quote \ backslash \ddd Octal character (ddd) \uxxxx Hexadecimal UNICODE character (xxxx) What is Next? This chapter explained the various data types. The next topic explains different variable types and their usage. This will give you a good
End of data type / variable Tutorial:- 5
Format Spec fire In Java
-
Today use to printf method .
-
System.out.printf(“folat num = %f, f)
-
Format specifire holo %f
-
Format specifire must be used printf,
Not for println, print -
Char %c, c, value print
-
Boolean %b, b
-
Int , sort, byte, long – 4 ti holo int data type er purrnoo number. %d
-
Float %f, then value print.
-
Double %f
-
String %s
Example: package FeburaryJAVA;
public class FormatSpecifire4 {
public static void main(String args[]){
boolean b = true; char c = 'B'; double num = 10.2562548; int result = 100; float f = 10.26f; byte by = 5; short s = 25; long l = 200;
System.out.printf("boolean num = %b\n",b);
System.out.printf("Character c = %c\n",c);
System.out.printf("double result of = %f\n",num);
System.out.printf("Integer value is a =
%d\n",result);
System.out.printf("folat value is a = %.2f\n",f);
// 2 numb menas 2 num point i can see
System.out.printf("Byte value is a = %d\n",by);
System.out.printf("Short value is a = %d\n",s);
System.out.printf("Long value is a = %d\n",l);
} }
The End Of java format specifier Tutoria - 06
System.out.println("Enter your data"); Scanner sc = new Scanner(System.in);
long l = sc.nextLong(); System.out.println("Long value = "+l);
short s = sc.nextShort(); System.out.println("Short data : "+s);
System.out.println("Byte data : "+n);
float fl = sc.nextFloat(); System.out.println("Float data: "+fl);
String name = sc.nextLine(); System.out.println("String data: "+name);
double res = sc.nextDouble(); System.out.println("Double data : "+res);
System.out.println("Int data: "+num);
https://www.tutorialspoint.com/java/util/java_util_scan ner.htm
- Scanner class use korte hobe.
- package FeburaryJAVA;
import java.util.Scanner;
public class UserInput {
public static void main(String args[]){
double number ;
Scanner st = new Scanner(System.in); System.out.println("Please double number"); number = st.nextDouble();
System.out.println("this double number :
"+number);
String name ;
Scanner sc = new Scanner(System.in); System.out.println("please your name"); name = sc.nextLine();
Operator:- +,-,*,/ , = ei gulo operator. Operand:- jader niye + ,- kora hoy take operand bole Constant value:- j man paoa jabe with equal (=) er pore jeta thakbe seta amder constant value . Expression:- operator , operand, Constant value niyei amder Expression.
- Type of Operator : 8 type’s are opertor in java.
Example:-
System.out.println("Enter your data: ");
Scanner sc = new Scanner(System.in);
int a,b, res; a = sc.nextInt(); b = sc.nextInt();
// addition
res = a+b; System.out.println("Addition: "+res);
res = a-b; System.out.println("Subtraction "+res);
res = a*b;
System.out.println("multiplication: "+res);
double ans = (double) a/b; // convert to - int to double
parse // type cust to int to double System.out.println("Division : "+ans);
res = a%b;
System.out.println("Modulas : " +res);
= Assign operator += plus Assign Operator -= minus Assign operator *= multiply assign operator /= division assign operator %= modulus assign operator
Example:-
//java Alignment operator int x = 5; int y = 3;
// plus alignment operator then x er man asign hosse.. x += y; // x = x+y = 8 System.out.println("x plus : " + x);
// minus alignment operator x-=y; // x = x-y = 8-3 = 5 System.out.println("x minus : "+x);
// multiply alignment operator x*=y; //x = xy = 53 = 15 System.out.println("x multi : "+x);
// division alignment operator x/=y; //x = x*y = 15/3 = 5 System.out.println("x div: "+x);
// modulus alignment operator x%=y; // x = x%y = 5%3 = 2 modulus 2 System.out.println("X mod: "+x);
https://gist.github.com/uzzalmondalcse/c3 40e3058f4364d37126258067dc1a1b Temperature programming solve, show to gist… https://gist.github.com/uzzalmondalcse/6a24d353 3690f21da3f4017fa3aedd71
The end of Tutorial 07: Arithmetic with assignment oPerator....@@@@####
Unary:- akti mattro operand er sathe Jodi kono operator add kora hoy tahole unary operator bola hoy like +a;
unary operator j man thakbe Jodi plus hoy tahole gun korbe minus hole minus gun korbe.. Example:-
//Unary Operator + , - int x = -10; int res;
res = +x; System.out.println("Unnary plus: "+res);
res = -x; System.out.println("Unnary minus: "+res);
Increment :- ++; Unary plus er sathe ak ak kore barano hoy.
Decrement: -- Unary minus er sathe ak ak kore komanohoy.
++a – Jodi kono variable er age bose prefix increment operator. Age bosle ak jog hoye jai
--a – Jodi kono variable er age bose prefix decrement operator..
a ++ - Jodi kono variable er pore bose postfix increment operator.
a-- - Jodi kono variable er pore bose postfix decrement operator.
++x = valur man agei barbe , and valu ter sathe add hobe.. etake bola hoy prefix.
X++ = valur man agei barbena , pore barbe othat pore Jodi kono value pai tahole sei valur sathe add hoe e joono etake bola hoy postfix
Unnarry Operator Unary +, unary – Unaary ++; Unaary--
- Akti mattro operand er sathe j man gun kora hoy take unnnary operator bole
Like - +a; -b; *c; /d
package FeburaryJAVA;
public class unaryOperator {
public static void main(String args [ ]){
int a=10, b=-5, result;
result = +a;
System.out.println(result);
result = -b;
System.out.println(result);
}
}
- prefix = ++a
- postfix = a++;
- prefix holo man pabe barbe…
- postfix holo sathe sathe noy pore Jodi oi valur man assign hoy tokon se barbee.
public class unaryOperator {
public static void main(String args [ ]){
//unnary ++; unnarry -- operator.
// prefix ++a; postfix a++
int a=10, b;
b = a++; //11
System.out.println("B = "+b);
b= ++a; //11
System.out.println("B = "+b);
b = --a;
System.out.println("B="+b);
Tutorial:v08 unary programming now End..
Scanner sc = new Scanner(System.in); System.out.println("Enter a num"); int num = sc.nextInt();
if (num%2==0){
System.out.println("Even num"+num);
}else if(num%2!=0){
System.out.println("Odd num "+num);
}else {
System.out.println("The input is not correct");
}
//Vowel and consonant
Scanner sc = new Scanner(System.in); System.out.println("Please input letter "); char v = sc.next().charAt(0);
if (v=='a' || v=='e' || v=='i' || v=='o' || v=='u'){
System.out.println("Vowel "+v);
}else if(v=='b' || v=='c' || v=='d' || v=='f' || v=='j' || v=='h'
|| v=='i' || v=='j' || v=='k' || v=='l' || v=='m' || v=='n'
|| v=='p' || v=='q' || v=='r' || v=='s' || v=='t' || v=='v'
|| v=='w' || v=='x' || v=='y' || v=='z' ){
System.out.println("Consonant "+v);
}else {
System.out.println("hey , your cannot input vowel and consonant ");
}
Tutorial end 10 .. Control statement if else Done
-
Dui ba totodhik condition er moddhe shomporko sthaponer jonno logical Operator use kora hoy.
-
Java te 03 dhoroner logical operator ase,
-
Logical AND-&&, OR-||, NOT -!.
- Dui ba totodhik condition jokon true hobe tokon seta ke amara logical and operator bole thakbo. Condition jotogula thakbe true hole amder j statement tahkbe statement tokon kaj korbe.
- Akta false then statement is false .
- All item’s are true then statement is true.
3. All Condition true hole ture , statement er moddhe dukhbe, akta condition false hole statement er moddhe dukhbena.
Example 02:-
package FeburaryJAVA;
public class logicalAnd {
public static void main(String args[]){
int num1 = 10, num2 = 20, num3 = 30; boolean result;
result = ((num1!=num2) && (num2!=num1) &&
(num3>num2));
System.out.println(result);
result = ((num1!=num2) && (num2!=num1) && (num3==num2));
System.out.println(result);
}
}
- Onek gulo condition thakbe amder j kono akta true korar projon hobe e jonno amra logical Or ei Operator bole thakbo. R j kono akta true hole amder condition er statement kaj korbe
- Sob gulo theke akta item Jodi true hoy tahole true.
- Sob gulo item Jodi false hoy tahole false ashbe.
Example:-1 package FeburaryJAVA;
public class LogicalOperator {
public static void main(String args[]){
//Logical operator..
int num1 = 1, num2 = 5, num3 = 10; boolean result;
result = ((num1>=num2) || (num2>=num3) ||
(num3>=num1));
System.out.println(result);
result = ((num2<=num1) || (num3<=num2) ||
(num3<=num1)); System.out.println(result);
}
}
- Kono item soman noy take logical not equal bola hoye thake.
- Jodi soman thake tahole stamen kaj korbena r Jodi not equal soman na hoy tahole ter statement kaj korbe..
End of Tutoiral 11 logical operator.
Switch Case In Java 20.02.19
-
Switch, case, break, default, – 04 keyword sure neccessare
-
break and default mandatory.
-
If-else er motoni switch statement tobe switch case er maddhome amra if-else er moton ei kaj chelate pari.
-
Switch statement excite one statement of multiple conditions
-
Keyword statement to on other switch statement
-
switch(expression){ } switch er moddhe kono akta value / experrision amara patch korbo.
-
Switch block er moddhe onek gulo condition thakbe / onek gulo case thakbe. Jamonta if er moddhe koresilam.
-
Amra j value ta pass korbo seta Jodi
Ei valur sathe match hoy tahole amader statement kaj korbe and break korbe. Othat nise jaoar r kono projon nei. Amder condition/ expression onujahi Jodi expression match kore thole sei case er/ statement ti kaj korbe and break hobe nise jaor projon hobena. -
Erokom onekgulo case use korte paril, Jodi kono case er sathe match na kore tahole amara jeta use korbo seta holo default. Onekta else er moton. Sure kaj korbe.
Tutorial - 12
End of Java Switch..
-
Conditional operator kea amara Ternary operator bole thaki.
-
experession1? expression2: expression3
-
ei 3 ta operand niye kaj kore bole eke a amara ternary operator / conditional operator bole thaki.
-
? – if er motn kaj kore,
-
: - else er moton kaj kore.
-
experession1 jodi true hoy – expression2 eita kaj korbe
-
experession1 jodi falase hoy – expression3 eita kaj korbe.
Example:-
Fast exp y er thke x boro tahole x kaj korbe , Jodi fast condition false hoto tahole y er man kaj korto..
Example code:
package FeburaryJAVA;
import java.util.Scanner;
public class CoditonalOperrator {
public static void main(String args[]){
int num1,num2,large;
Scanner sc = new Scanner(System.in);
System.out.println("Enter two number data:- "); num1 = sc.nextInt(); num2 = sc.nextInt();
large = (num1>num2)? num1 : num2;
System.out.println("Large Nume: - "+large);
}
}
Java Ternary / Conditional operator end Now… Tutorial 13
Java Math Class
-
https://docs.oracle.com/javase/8/do cs/api/java/lang/Math.html
-
Java Maximum and Minimum
int max = Math.max(x,y);
int min = Math.min(x,y);
// absulate value. int abs = Math.abs(y); System.out.println("Absoulate value = "+abs);
// power class Int x = 2, y = 3
double pow = Math.pow(x, y);
System.out.println("Power = "+pow);
Ekhane power mane x = 2 and y er man 3 . akon 2 er power hobe y er value 3 23 = 8.
5. Math class er round niye kaj korbo. Round holo float type er akta man k se int e return kore and kaskasi kono sonkha 5.5 hole se 6 output dai.
//round class
float ro = Math.round(5.5f);
System.out.println("Round class = "+ro);
- // pi class double pi = Math.PI;
System.out.println("pi valu of :-"+pi);
All example:
package FeburaryJAVA;
public class MathDemo {
public static void main(String args[]){
int x = 2, y = 3;
int max = Math.max(x,y); int min = Math.min(x,y);
System.out.println("Maximum value = "+max); System.out.println("Minium value = "+min);
// absulate value.
int abs = Math.abs(y);
System.out.println("Absoulate value = "+abs);
// power class
double pow = Math.pow(x, y); System.out.println("Power = "+pow);
//round class
float ro = Math.round(5.5f);
System.out.println("Round class = "+ro);
// pi class double pi = Math.PI;
System.out.println("pi valu of :-"+pi);
}
}
Tutoiral 14 now End Java Math Class..
- Loop er sahajee kono akta kajke amara bar bar sompdhon korte pari. Kono akta statement ba multiple statement k amara bar bar sompodhon korte pari.
- For loop er jono amder jeta projon seta holo first for keyword projon.
- Akta for loop er 3 ta part thake,
hobe
condition – akta loop kotobar cholbe ta depend korbe ei condition er upor. must be true to condition.
kintuo initialized part a akbari jabe second bar r jabena. Jotobar vitore jak na kno condition true hole se jeteparbe. Vitore ashbe statement print korbe .. Then protibar increment / decrement part intilize hobe, mane 1 , 1 kore barbe.
Example that: package FeburaryJAVA;
public class someOfNumberFor {
public static void main(String args[]){
// for (int i = 1; i<=10; i++){ // // // if(i%2==0){ // // System.out.println(i); // } // // // }
// for (int i = 0; i<=10; i++){ // // System.out.println(i); //
// if (i==5){ // break; // } // // } System.out.println("loop over");
// int i, j; // // for (i= 1; i<=5; i++){ // // for (j=1; j<=5; j++){ // // if (i==1 || i==5 || j==1 || j==5){ // // System.out.print("*"); // } // // else { // // System.out.print(" "); // } // } // // System.out.println(); // }
// int i,j; // // for( i = 1; i<=5; i++){ // // for (j=1; j<=5; j++){ // // if (i==1 || i==5 || j==1 || j==5){ // // System.out.print("*"); // }else{ // // System.out.print(" "); // } // // if (j==5){ // System.out.println(); // } // } // }
// for (int i = 5 ; i>=1; i--){ // // for (int j=i; j>=1; j--){ // // System.out.print("*"); // } // // System.out.println(); // }
// for (int i =0; i<=5; i++){ // // for (int j=1; j<=i; j++){ // // System.out.print("*"); // } // // System.out.println(); // }
// for (int i = 0; i<=20; i++){ // // // if (i%2==0){ // // System.out.println("Even num "+i); // }else if(i%2!=0){ // // System.out.println("Odd num : "+i);
// }else{ // // System.out.println("Num isn't correct"); // } // // }
// int s=0, len; // len = args.length; // // for (int i =0; i<len; i++){ // // int x = Integer.parseInt(args[i]); // s = s+x; // } // // System.out.println("Sum of command line of arguments: "+s);
// for (int i=0; i<=10; i=i+2){ // // System.out.println("bangladesh : "+i); // }
}
}
Java Do While Loop 01.03.2019
-
int I =0; firstly initialize part
-
do{ //statement System.out.println(); i++; // increment -decremetnt }while(i<10);
-
do while loop akbarer jonno o print hobe , statement print hobe . r erpor Jodi condition false thake tahole se terminate hoye jabe . tokon r loop ti kaj korbena.
Tutorial - 17 Java while loop
Java while loop 01.03.2019
-
Firstly initialize part – i = 0
-
Secondly while(condition)
-
Thirdly body
-
Body er moddhe statement then increment / decrement .
-
Jotokhon porjonto condition part ture tahakbe totokhon porjonto loop ta cholte thakbe. Body er moddhe statement gulo print korbe . increment decrement part o thakbe bar bar update hobe.
-
Jokon condition false hobe tokon r body er moddhe jabena.
-
While loop bade porer j code gulo tahkbe oi gula print hote thakbe.
Break and continue statement
Example: package FeburaryJAVA;
public class breakAndContinueStatement {
public static void main(String args[]){
for (int i = 100; i>=80; i--){
if (i==90){ continue;
}
System.out.println(i);
}
// for (int i = 0; i<100; i=i+2){ // // // if (i==10){ // // break; // } // // System.out.println(i); // // }
}
}
the end of Tutorial 18
-
Using Array – int[] num = new int[10];
-
Delcear Array – int [] num; String[]names
-
Create – num = new int[10];
-
Num[10] – size – 10 ta value ase amar.
-
Num[0] – index/subscript – 0,9 porjonto 9 ta index create korte hobe. Kom hole no prob, beshi hole out of exception dibe.
-
Array index print – just print array index
-
Array size print – length diye array size print
-
Array all data sum print – all data sum are print.
-
Array holo collection of variable of same data type. Onek gulo variableer collection ke array bola hoy.
-
Int type er array er jonno sudhumattro int type variable gulo rakte parbo, string hole string type er variable rakhte hobe.
-
Int [] number = new int[10];
Ekhane ami array te 10 ti value pass kore disi..
Int num = 10; Int[] num = new int[10] - Array declare . String[] names = new String[“Uzzal”]
Num[0] = 10; Num[1]= 20; Int length = num.length; System.out.println(length) // then array length
Int sum = num[0]+num[1]; System.out.println(sum)
-
Array size beshi nile problem nei , kintuo Jodi array er size kom nei r index Jodi beshi nei tahole array out of bound exception dibe.
-
Int[] num = new int[10]; String[] name = new String [5];
Example:
- Array index print
- Array size
- Array Jogfol
package Java67Today;
public class Array {
public static void main(String args[]){
int[] num = new int[5]; // array declear and create.//this is array size.
num[0] = 10; // this call of array index num[1] = 15; num[2] = 30; num[3] = 45; num[4] = 50;
System.out.println("Index of four: "+num[3]);
int length = num.length;
System.out.println("Array of length: "+length);
int sum = num[0] + num[1] + num[2] + num[3] + num[4];
System.out.println("Array of sum : "+sum);
}
}
The End of Tutoiral 20 Java Array Java 21 Tutorial Java Array and Avg
Java Array Finding Sum Avarage:- 52 num
-
Array sum and average print kora.
-
Array declear kore length er madhome call kora.
-
Jotogulo num jog hobe thik sei gulo num diye vag korle average ber hoy. Say 5 ta num sum hose 5 num diye vag kore average ber korte hobe.
-
Example num of Array,- length,sum , avg
package FeburaryJAVA;
import java.util.Scanner;
public class ArrayAditionAvg {
public static void main(String args []){
Scanner sc = new Scanner(System.in);
System.out.println("Enter data num :- ");
double [] num = new double[5];
// array length;
for (int i=0; i<num.length; i++){
num[i] = sc.nextDouble();
}
double sum = 0;
// array of add number
for (int i = 0; i<num.length; i++){
sum = sum+num[i];
}
//average num of:-
System.out.println("The array num of :" + sum);
System.out.println("The avarrage num of:"+sum/num.length);
}
// Scanner sc = new Scanner(System.in); // System.out.println("Enter data : ");
}
- Scanner class crate
- System, how many num ip user
- Array declare
- Index crate with input create
//How to use input in Array and 05 num .and check out average with sum /*
-
scanner class
-
want to num user 3.Array declare 4.index create with input create */
// scanner class Scanner sc = new Scanner(System.in); //want to num user System.out.println("Enter your 5 num"); //array declare int[] num = new int[5];
// num[0] = sc.nextInt(); // num[1] = sc.nextInt(); // num[2] = sc.nextInt(); // num[3] = sc.nextInt(); // num[4] = sc.nextInt();
int sum = 0; int avg = 0;
for (int i = 0; i<num.length; i++){
num[i] = sc.nextInt();
sum = sum+num[i];
System.out.println("Sum of array : "+sum); }
//average check out , divided to array lenght.
avg= sum/num.length;
System.out.println("Sum of average : "+avg);
Tutorial 21 Now End.
If we want:- Int [] num = {10,20,30,40,5,20};
-
Array / collection er jonno forEach loop use kora hoy.
-
Array declear kore for each loop er moddhe amara print korate pari.
-
Fast – for keyword.
-
Second – datatype and variable
-
: (colone) keyword ti use koretee hobe.
-
Je valur array rakha ase sei value ti dite hobe.
-
For each loop er moddhe print korte hobe.
-
Example : -
Example:- String [] names = {"Anis sir", "Muzahidul islam ","Shafins", "doc Sunnil "};
for (String name : names){
System.out.println(name); }
- Example:-
- int sum = 0; int num[] = {10,20,30,40,50,60,70,80,90};
for (int result : num){
System.out.println(result);
sum = sum+result;
}
System.out.println("sum = "+sum);
Tutorial 22 end now java for each loop
-
Array 02 proker, One dimontional Array. Multi dimontional Array..
-
Declaring 2d array int num [] [] = new int [2] [3] [2] – Row. [3] – Colum.
-
Array initialize:--
-
Array Introduction:-
-
Declearing Array : -
Creating Array : -
Array initialization:-
Tutorial 23 – 2D Array completed . Now End .
- Declare two arry two matrix. 2.User input A, B 3.Show to the row column input line 4.Matrix A,b with subtraction..
// jva bangla Array mattrix part 1
// declare to Array two mattrix int [][] A = new int[2][3]; int [][] B = new int[2][3];
Scanner sc = new Scanner(System.in); System.out.print("Enter your data : ");
// user input to: A System.out.println("Enter element for A Mattrix: -"); for (int row =0; row<2; row++){
for (int col = 0; col<3; col++){
//show to the row column in input line
System.out.printf("A[%d][%d]= ",row,col);
A[row][col] = sc.nextInt(); }
}
// show this Display A
System.out.println("A :"); for (int row=0; row<2; row++){
for (int col =0; col<3; col++){
System.out.print(" "+A[row][col]);
}
System.out.println( " " );
}
System.out.println(" \n ");
// user input t B: System.out.println("Enter element for B Mattrix: -"); for (int row =0; row<2; row++){
for (int col =0; col<3; col++){
//show to the row column in input line
System.out.printf("B[%d][%d] = ",row,col);
B[row][col] = sc.nextInt();
}
}
// println Matrix of B:- System.out.println("B: "); for (int row=0; row<2; row++){
for (int col = 0; col<3; col++){
System.out.print(" "+B[row][col]);
}
System.out.println(" "); }
--:Tutorial: 25 Array Matrix now End :--
//Array matrix with sub.....
//fast declare to array matrix int[][] A = new int[2][3]; int[][] B = new int[2][3]; int[][] C = new int[2][3];
Scanner sc = new Scanner(System.in); System.out.println("Enter input to Array Matrix elements ");
// user input to array matrix for A:- System.out.println("User input A :- "); for (int row = 0; row < 2; row++) { for (int col = 0; col < 3; col++) {
//A in row col print
System.out.printf("A[%d][%d] = ",row,col);
A[row][col] = sc.nextInt();
}
}
System.out.println("\n");
// user input to array matrix for B:- System.out.println("User input B:- "); for (int row = 0; row < 2; row++) {
for (int col = 0; col < 3; col++) {
System.out.printf("B[%d][%d] = ",row, col);
B[row][col] = sc.nextInt();
}
}
// Array matrix to show the Display:- A
System.out.print("A:"); for (int row = 0; row < 2; row++) {
for (int col = 0; col < 3; col++) {
System.out.print("\t" + A[row][col]);
}
System.out.println();
}
System.out.println("\n");
// Array matrix to show the Display:- B
System.out.print("B:"); for (int row = 0; row < 2; row++) {
for (int col = 0; col < 3; col++) {
System.out.print("\t" + B[row][col]);
}
System.out.println();
}
//Array matrix to sum print in show line... System.out.println("Array matrix are print subtraction: - "); System.out.println("Aray of sub - A+B: - "); for (int row=0; row<2; row++){
for (int col=0; col<3; col++){
C[row][col] = A[row][col]+B[row][col];
System.out.print("\t"+C[row][col]);
}
System.out.println();
}
Tutorial 26: now end ..
Java Array Matrix part 2 printed.
Diagonal – 1+5+9 is Diagonal elements.
If(row==col) Upper triangle – Di agonal elements er upore, 2+3+6 = 11
If(row<col) Lower Triangle- Daiagonal elements er nise lower Traiangle elements. 4+7+8 = 19.
Example: -
public static void main(String args[]) {
// row and col same its cal diagonal.
//diagonal , uppper, lower case..
Scanner sc = new Scanner(System.in);
System.out.println("Enter your num : - ");
// fast array create...
int [][] A = new int[3][3];
//user input to array create. for (int row = 0; row<3; row++){
for (int col = 0; col<3; col++){
//user input..
A[row][col] = sc.nextInt();
}
}
// initilize the diagonal, lower and upper
int diagonal = 0; int upper = 0; int lower = 0;
//diagonal , upper , lower case
for (int row=0; row<3; row++){
for (int col =0; col<3; col++){
// row and col same its cal diagonal. if (row==col){
diagonal = diagonal+A[row][col];
}
//row er cheye column er index boro - upper
if (row<col){
upper = upper+A[row][col];
}
//row er cheye column er index soto - lower.
if (row>col){
lower = lower+A[row][col];
}
}
}
System.out.println("Daigonal : "+diagonal);
System.out.println("upper : "+upper);
System.out.println("lower : "+lower);
}
}
Tutorial No 28
Array Output part – 01 Output:
0 1 2 3 4
5 6 7 8 9
10 11 12 13 14
15 16 17 18 19
Learn array:
1.Every value to 1, just create a initialize.
2. create to array 2 dimontional 4 row and 5 column.
3.Asigning value 2 array.
4. printing the elements row and column
// Array row column print..
//every value step to 1 just create a initlize. int k = 0;
//create to array 2 dimontinal 4 row and 5 column int [][] num = new int[4][5];
//crate iteratin loop in 4 row, 5 column //asigning to the value in 2d array ... for (int i=0; i<4; i++){
for (int j =0; j<5; j++){
num[i][j] = k; k++;
}
}
//printing the elements.. //2D array printing to row, column for (int i= 0; i<4; i++){ for (int j=0; j<5; j++){
// here is print num and row.
System.out.print("\t"+num[i][j]);
}
System.out.println(); }
- 2Daimontional array first check out row and column .
- Row declare must but column doesn’t declare no problem.
- Ouptpu:
0
1 2
3 4 5
6 7 8 9 // Array row column print..in 2D Diamontional new print..
//initilize array create just row, not column int [][] num = new int[4][];
//first row column declare.. // 0 num row a column thakbe 1 ta. // 1 num row a column thakbe 2 ta.
num[0] = new int[1]; num[1] = new int[2]; num[2] = new int[3]; num[3] = new int[4];
int k = 0;
//create row with every looping 1 add to column with asign to num..
for (int i =0; i<4; i++){
for (int j =0; j<i+1; j++){
// num asign korte hobe 1 , 1 kore barate hobe.
num[i][j] = k; k++;
}
}
for (int i=0; i<4; i++){
for (int j=0; j<i+1; j++){
System.out.print(num[i][j]+" ");
}
System.out.println();
}
Tutorial 29 is now end.
Array ascending / Descending:-
// sorting on array with print array max with min num.
// array declare int [] num = {10,-3,25,1,30};
// how to crate ascending or descending // at first call in Arrays.sort() method. //create to arrays sort method .
Arrays.sort(num);
System.out.print("Asecending:- "); for (int i =0; i<5; i++){
//Array ascending
System.out.print(" "+num[i]);
}
System.out.println();
System.out.print("Descending:- "); for (int i =4; i>=0; i--){
System.out.print(" "+num[i]); }
The Tutorial end of Soritn an array.. Tutorial end Num of 30 Complete in Array.
Array:-
-
Array is static .
-
Static thatmeans size fixed. Next ami change korte parbona.
-
Array size fixed thake.
1.ArrayList Dynamic.
2.ArrayList er size fixed noy, eta dynamic. Eta ami change korte parbo.
- Primary point ami jotogulo element add korte saiboo ArrayList a add korte parbo.
ArrayList number = new ArrayList(); ();- er moddhe size esse moton nite parbo.. ei jonno amra size nissina..
// if i print to array size.. System.out.println("Array size = "+num.size());
1.ArrayList create = ArrayList
2.Array size. = num.size();
-
Array add = num.add();
-
Array index display to show= num
5.display to many other Array = for each loop();
-
for loop to – iterator method declare.
-
removing element to aray index – num.remove();
-
all elements are removing aray - num.remove(num);
-
clear method call – num.clear();
// ArrayList create. ArrayList num = new ArrayList(); //size. // I don't size declare . I wish that get a size.
// if i print to array size.. System.out.println("Array size = "+num.size());
// we are display to show many other's things :01 /* how to adding to array elements method call to num. add().. with hoe to removing array elements method call to num.. rem(); */ num.add(10); // array idex 0 and num 10 num.add(12); // array idex 1 and num 12 num.add(15); // array idex 2 and num 15 num.add(3,100); // array index 4, element 100;// array index display show in print System.out.println(num);
// size print of array.. System.out.println("Array size = "+num.size());
// we are display to show many other's things :-
02 // use to for each loop
for (int res : num){
System.out.println("for each loop : "+res); }
System.out.println("Array size: "+num.size());
System.out.println("Array List Add to
Contains:"+num);
// iterator method to crate a for loop print now. system in: 03
// Iterator itr= num.iterator(); //arraylist er madhome iterator method k use korbo.
//then help to while loop and calling to hashnext method.
//when valu select to hasNext method create.
// while (itr.hasNext()){ // // //itr er every value want to print. // System.out.println("every itr value:" + itr.hasNext()); // }
//removing element to Array list in Array
num.remove(0);
System.out.println("Array List remove to
Contains:"+num);
//all array list are remove in remove();
// num.remove(num); // System.out.println("Array List all Remove Contains:"+num);
// basic ArrayList in java /*ArrayList
-
create-ArrayList num=new ArrayList();
-
size output- num.size
-
elements add – num.add * print and contains- num.contains(30)- Boolean return.
-
size
-
remove – num.remove(2); - index
-
all size of remove – num.remove();
-
Clear method – num.clear(); * isEmpty - if any value storage return false, any value null retrun true,
-
ArrayList contains - ArrayList er size a 30 value thakle true, na thakle false.
-
set method - Arralist in any index set of value, that means replace method.
-
get method – index er value pabo.
-
*/
ArrayList num = new
ArrayList(); //if any value don't storage, there is no problem show in ArrayList.
//size output:- System.out.println("ArrayList size: "+num.size());
//arrayList elements add num.add(0, 10); num.add(1, 20); num.add(2, 30); num.add(3, 40); num.add(4, 50);
//arraylist size. System.out.println("Array List size :- " + num.size());
System.out.println("Array List contains : " + num); //isEmpty(); /* ArrayList empty return true, ArrayList any value storage return false*/ boolean con = num.isEmpty(); System.out.println("condition is empty method: "+con);
num.set(3,100); // replace System.out.println("Seeter method , replace call : "+num);
int gets = num.get(0); // get in method. System.out.println("Index of 0 :- "+gets);
int indexpos = num.indexOf(30); System.out.println("Index of ArrayList
: "+indexpos);
/*list in storage if any element are return true , other return false. */ boolean cont = num.contains(30); System.out.println("30 is in the line:- "+cont);
System.out.println("ArrayList remove index :- " + num);
System.out.println("ArrayList Remove all : " + num);
System.out.println("After clear Array: "+num);
/*
- use to add method.
- use to addAll();
- use to equal method . - if any method equal , equal - retutrn boolean value true, other wise false. * */
ArrayList num1 = new ArrayList<>(); ArrayList num2 = new ArrayList<>(); ArrayList num3 = new ArrayList<>();
// add method call num1 num1.add(10); num1.add(20); num1.add(30); num1.add(40); num1.add(50); System.out.println("Add method : "+num1);
// add method call num1 num2.add(60); num2.add(70); num2.add(80); num2.add(90); num2.add(100); System.out.println("Add method : "+num2);
// num3 and num1 similar to print create to.. addAll(); num3.addAll(num1); System.out.println("all method are print: "+num3);
//equal mehtod create to boolean result, either true are false. boolean res = num1.equals(num2); System.out.println("Num1 = Num2 : "+res); boolean result = num1.equals(num3); System.out.println("num1 == num3: "+result);
That’s means – ascending or descending.
// Sorting an arrayList
/*hoy soto theke boro othoba boro theke soto num a sajano thakbee
-
That's means ascending or descending
-
collections.sort(); - ascending
-
Collections.sort(num, Collections.reverseOrder()); - descending Collections.sort method call then arralist pass then Colletions.reverseOrder ei method ti call hobe - * */
//arrayList create. ArrayList num = new ArrayList<>();
//arrayList add num.add(10); num.add(- 20); num.add(30); num.add(40); num.add(50);
System.out.println("before sorting : "+num);
collections.sort(); Collections.sort(num); System.out.println("Ascending sorting : "+num);
Collections.reverseOrder()); System.out.println("Descending sorting "+num);
in java programming
1.String 2.String Buffer 3.String Builder
- char type Array calls are String.
- value string - String name = "uzzal"; 6.object string - String n = new String (" Uzzal"); 7.char type array ke string bola hoy - char [] name = {'a','b'}
8.length(); - coName.length();
9.coName , obj jodi akoi hoy tahole 3 system ase print kora jabe..
coName and obj ke reference bola hoy refernce gulo akoi na tai not equal print hobe.
10.equalS();- coName.equals() - value compare korte hobe equal mehtod er moadhhome.
-
contains method call korbo. kaj holo coName er moddhe obj er kisu ase kina jodi thake true return korbe.
-
equalsIgnoreCase() call some data are ignoe. upper case lower case ignore korbe.
-
contains mehtod coName er moddhe Techoners thake tahole return korbe true r ta na hole false. boolean res = coName.contains("Techoners");
14.// is empty (); //coName - if any data sotrage return false, don't data storage return true. */
String coName = "Techoners Wordpress"; System.out.println("valu Stirng : -"
- coName);
String obj = new String("Techoners Wordpress"); System.out.println("Object Stirng : -" + obj);
//char type array ke string bola hoy char[] name = {'u','z','z','a','l'}; System.out.println(name);
// some knwon to method String ..
// string length int len = coName.length(); System.out.println("String length : "+len);
// coName , obj jodi akoi hoy tahole 3 system ase print korar..
//compareTo, equals, == ;
// coName and obj ke reference bola hoy refernce gulo akoi na tai not equal print hobe.
if (coName==obj){
System.out.println("Equals");
}else{
System.out.println("Not
Equals"); }
//value compare korte hobe.. equals() - ei mehtod er maddhome..
if (coName.equals(obj)){
System.out.println("Equals");
}else{
System.out.println("not
Equals"); }
// contains method call korbe. // kaj holo coName er moddhe obj er kisu ase kina jodi thake true return korbe.
if (coName.contains(obj)){
System.out.println("Correct contains"); }else { System.out.println("Incorrect contains");
}
//equalsIgnoreCase() call some data are ignoe. upper case lower case ignore korbe.
if (coName.equalsIgnoreCase(obj)){
System.out.println("Ignore Case
"); }else{
System.out.println("Not Ignore case ");
}
//contains mehtod // coName er moddhe Techoners thake tahole return korbe true r ta na hole false. boolean res = coName.contains("Techoners"); System.out.println("Contains method: "+res);
// is empty (); //coName - if any data sotrage return false, don't data storage return true. boolean ie = coName.isEmpty(); System.out.println("if any data sotrage: - "+ie);
End of java String part 1.
// String part 2: /*
- String er maddhome jog possible.. * concat(); - concat method er o jog possible *toUpperCase(); - upper case er
madhome sob kisu boro hobe.. *toLowerCase(); - lower case er madhome sob kisu soto hobe.. * startWith(); - first word capital hole / or same word then true, r ta na hole false
- endsWith(); - lettr jodi matched hoy true then other wise return false. * String array declare and for each loop use - name[i]
- */
String firstName = "Uzzal"; String lastName = " Mondal";
String name = firstName + lastName; System.out.println(name);
System.out.println();
// String er madhome Concat possible.. //concat(); String resname = firstName.concat(lastName); System.out.println(resname);
System.out.println();
//String er full name ti puropuri upper case korbo.. //resname.toUpperCase(); String upper = resname.toUpperCase(); System.out.println(upper);
System.out.println();
//String er full nate ti puropuri lower case korbo... //resname.toLowerCase(); String lower = resname.toLowerCase(); System.out.println(lower);
System.out.println();
//String er value startWith (); - fast word capital hole true na hole false return. //startWith(); boolean b= firstName.startsWith("U"); System.out.println(b);
System.out.println(); //String er value startWith (); - word don't match return false. //startWith(); boolean bRes= firstName.startsWith("u"); System.out.println(bRes);
System.out.println(); //String er value endsWith (); - last word match //endsWith(); boolean lname = lastName.endsWith("l"); System.out.println(lname);
String [] names = {"Shuvash", "Shaptami","uzzal","suzal","Mondira"};
for (int i = 0; i<5; i++){
System.out.print(names[i]);
}
System.out.println("forseach");
for (String allName : names){
System.out.print(","+allName);
}
trim(); - samne and pise se jaiga remove korbe but middle point a noy. chartAt(0) – 0 index er char find korte parbo. codePointAt(0) – 0 index er asci value return korbe.
indexOf(‘n’) – n er index/pos num ta bole dibe lastIndexOf(‘n’) – last er index/pos num ta bolbe.
String name = " Techoners is well for Web Development ";
String t = name.trim(); System.out.println(t);
#// chartAt(0); // 0 index er char ti find korbe. char n = name.charAt(0); System.out.println(n);
System.out.println();
//0 index er asci value return korbe. int a = name.codePointAt(0); System.out.println(a);
System.out.println(); //indexOf(‘e’) – e er index/pos num ta bole dibe int m = name.indexOf('e'); System.out.println(m);
//last er index/pos num ta bolbe. int e = name.lastIndexOf('e'); System.out.println(e);
/*
-
replace(); - 2 ta paramiter chai i place j include korle j all times print hobe i er khane.
-
split(); - akta string ke onek vabe bivokto korte parboo..
-
then return korbe akta string[] - string array. *
-
*/
String s1 = "Techoners is my favourite place"; System.out.println(s1);
//replace(); String a = s1.replace("o","r"); System.out.println(a);
//split(); - string er moddhe jeta pass seta remove hoye jabe // return korbe string[] String sp = "hello, I am including in Techoners, I hope its my pleasure"; String[] spl = sp.split(",");
for (String res : spl){
System.out.println(res);
}
-
String is not changeable. With , object k niye j kono akta value , datatype er moddhe rakhte hoy. then print korte hoy.
-
Example: String name = “uzzal”; String std = name.replace(z,j); Ekhane std er moddhe value change kora jabena.
-
String Buffer is changeable,
Create:- StringBuffer sb = new StringBuffer(“uzzal”) Ekhane sb object niye sob value print kora jabe.. -
StringBuffer sb = new StringBuffer("Uzzal Mondal");
-
String there is no change, but String Buffer is changeable.
-
String buffer and string add
-
appeand() - int / string sob value kaj kora jabe..
-
delete() - ei index theke oi index delete 0,4
-
length() - seLength - how many length told cm
-
reverse() - ultano print hobe
String cName = "Techoners is my best place "; StringBuffer sb = new StringBuffer(cName);
System.out.println(sb);
// onno datatype er sathe kaj kore.. //string
sb.append("Thank's to chance in you place ");
//int sb.append(10);
System.out.println(sb);
// 0 index theke koto index porjonto delete seta bolte hobe sb.delete(0,4);
System.out.println(sb);
System.out.println(sb);
System.out.println(sb); Tutorial 42
String : palindrome
String er moddhe value nibo. String s = “madam”;
StringBuffer sb = new StringBuffer(s);
sb.reverse();
akta String variable er vitore jokon rakhbo tokon , String variable a StringBuffer er value rakhte dibona. E jonno amake jeta use korte hobe seta holo toString();
if-else condition chalabo, equals(); method er maddhome. Palindrome check Example:
/* Stirng delcare
StringBuffer Declare
reverse(). method call and String buffer er value string er moddhe rakhte parbona tai amara toString method call korbo.
check to palindrome in reverse method..
*/
String name = "1221";
//String buffer declare
StringBuffer sb = new StringBuffer(name);
/*reverse(). method call and String buffer er value string er moddhe rakhte parbona tai amara toString method call korbo.*/
String res = sb.reverse().toString();
// check to palindrome in reverse metho
if (res.equals(name)){
System.out.println("Palindrome");
}else{
System.out.println("not plaindrome"); }
- Stirng builder er subidha eta akti change able.
- appeand(); - int,string,char, double sob gulo value call korte pari.
/*
StringBuilder...
appeand() - int, double, String all datatype value we want to call it.
StringBuffer er moton all method supported.
reverse() -
*/
String name = "techoners"; StringBuilder sb = new StringBuilder(name);
System.out.println(" range : "+sb);
//apeand(); sb.append(" mondal,"); sb.append(10+","); sb.append(12.10);
System.out.println(sb);
//reverse();
String rv = sb.reverse().toString(); System.out.println("Reverse : "+rv);
//delete
String dl = sb.delete(0,6).toString();
System.out.println(dl);
//Java wraper class:--
/*
-
java oop language , eta object use niye kaj kore..
-
java te sobgulo object niye kaj korbe.
-
primitive datatype to object convert.
-
Object to primitive datatype convert.
-
we try to know that, wrapper class, autoboxing, outboxing
6.autoboxing - primitive data type theke jokon object a jabo tokon-> autoboxing.
7.outboxing - object theke jokon primitive data type a jabo tokon-> outboxing.
- j class er name sei class er value likte hobe
- Double y = Double.valueOf(x); */
// primitive to convert -> object with call> autoboxing.
//valueOf(); int x = 30;
Integer y = Integer.valueOf(x);
System.out.println(y);
//method don't declare to work //automatic primitive to obj -> call of autoboxing int z = x; System.out.println(z);
// Object to -> primitive datatype ->Outboxing Double d = new Double(10.26); System.out.println(d); //outboxing double e = d.doubleValue(); System.out.println("double value "+e);
//don't decalre to doubleValue(); double de = e;
System.out.println(de);
Important Tutorial : 45 Primitive to String String to Primitive
Primitive to Stirng:
/*
-
primitive to Stiring .
-
String to primitive.
*/ // primitive to String. int x = 10; // String a convert korar jonno amara toString(); method call korbo., String s = Integer.toString(x); System.out.println(s); //primitive double to convert to string double i = 20; String res = Double.toString(i); System.out.println(res);
//primitive float to convert String float f = 12.12f; String fl = Float.toString(f); System.out.println(fl);
//primitive char to Convert String char c = 'a';
String ch = Character.toString(c);
System.out.println(ch);
//primitive byte to String byte b = 2;
String bt = Byte.toString(b); System.out.println(bt);
//primitive short to string convert short sh = 5;
String st = Short.toString(sh);
System.out.println(st);
//primitive long to Stirng convert long l = 120L;
String ln = Long.toString(l);
System.out.println(ln);
//primitive boolean to Stirng convert.. boolean bl = true; String bla = Boolean.toString(bl); System.out.println(bl);
String to primitive:-- /* primitive to Stirng convert -> to String method; String to primitive convert -> parseInt(), parseDouble(); value of(); */
//String to primitive
// Integer.parseInt();
String s = "32"; int nm = Integer.parseInt(s); System.out.println(nm);
//double
String cm = "25";
double db = Double.parseDouble(cm);
System.out.println(db);
//float
String f = "20.56"; float fl = Float.parseFloat(f); System.out.println(fl);
//binary to decimal format
String bin = "1010";
Integer decimal =
Integer.parseInt(bin,2); System.out.println("Decimal "+decimal);
//octal to decimal format String oc = "101011"; Integer ot = Integer.parseInt(oc,8); System.out.println("octal " + ot);
//hexadecimal to decimal format
String hex = "A";
Integer hd = Integer.parseInt(hex,16);
System.out.println("hexa decimal "
+hd);
// decimal to binary.
// toBinaryStirng(); -> return korbe akta string..
int decimal = 15;
String binary =
Integer.toBinaryString(decimal); System.out.println("Binary num : - "+binary);
//decimal to octal
Scanner sc = new Scanner(System.in);
System.out.println("Enter Octal num input: - ");
int decimall = sc.nextInt();
String octal = Integer.toOctalString(decimall); System.out.println("Octal : "+octal);
// decimal to hexadecimal num int dec = 15;
String hex = Integer.toHexString(dec);
System.out.println("hexa decimal num
:- "+hex);
// current date show ..
Date date = new Date();
System.out.println(date);
//Date format..
DateFormat df = new
SimpleDateFormat("dd/MM/YYYY"); String currentDate = df.format(date); System.out.println("current date : "+currentDate);
// Time
//localtTime.now()
LocalTime time = LocalTime.now(); System.out.println("local time "+time);
//format time..
DateTimeFormatter dtf =
DateTimeFormatter.ofPattern("hh:mm:ss"); String formatedTime = time.format(dtf); System.out.println("Time "+formatedTime);