Learning Java

Java basic

This is the content of java basics

Hello world

This is the how you write a hello world. In this program, we will print the Hello world in the terminal.

public class HelloWorld {
  public static void main(String[] args) {
    System.out.println("Hello world");
  }
}

Addition

    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        System.out.println("What do you want? add or subtract?");
        String operation = scanner.nextLine();
        
        if (operation.equals("add")) {
            // Adding here.
            System.out.println("Type first number to add: ");
            int a = Integer.valueOf(scanner.nextLine());
            
            System.out.println("Type second number to add: ");
            int b = Integer.valueOf(scanner.nextLine());
            
            System.out.println("Bro, your addition is: " + (a + b));
        } else if (operation.equals("subtract")) {
            // Subtract here.
            System.out.println("Type first number to subtract: ");
            int a = Integer.valueOf(scanner.nextLine());
            
            System.out.println("Type second number to subtract: ");
            int b = Integer.valueOf(scanner.nextLine());
            
            System.out.println("Bro, your subtraction is: " + (a + b));
        } else {
            // Not supported operation.
            System.out.println("Unsupported operation: " + operation);
        }
    }

Editor, Debugger, Compiler, Runner

JDK JRE

Language -> Assembly language Java is a high level language -> low level language (Assembly language)

Java(high) -> Java compiled file (intermediate) -> Assembly(low level)

Build -> Java file ko class file me convert karta hai .class is the intermediate part

javac HelloWorld.java -> Build aka Compile -> Conversion to intermediate language java HelloWorld -> Run the HelloWorld.class file java HelloWorld.java -> Build and run the HelloWorld.java

Java advanced

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