Custom printf
Name: _printf
What is printf? printf is the C language function to do format-ted printing.
The same function is also available in PERL.-
Secrets of “printf” by Professor Don Colton.
Prototype: int _printf(const char *format, ...);
This prototype is an implementation of the printf standard function and variadic function @format is a character string. The format string is composed of zero or more directives.
The real power of printf is when we are printing the contents of variables - Professor Don Colton
how does printf works?
In the most simple case, printf takes one argument:a string of characters to be printed. This string iscomposed of characters, each of which is printed ex-actly as it appears.- Secrets of "printf"
Description.
The function _printf writes output to standard output. The function writes under the control of a format string that specifies how subsequent arguments (accessed via the variable-length argument facilities of stdarg) are converted for output
Return:
Upon success, returns the number of characters printed (excluding the null byte used to end output to strings)
conversion specifiers handling:
. c - prints a character. i.e _printf("%c", 'A'); . s - prints a string. i.e. _printf("%s", "Hello World!"); . % - prints a percent. i.e _printf("20%%"); . d - prints intrgers. i.e _printf("%d", 20); . i - prints signed integers. i.e _printf("%i", 1234567890); . b - the unsigned int argument is converted to binary . u - prints unsigned integers . o - prints octal . x - prints hexadecimal lowercase . X - prints hexadecimal uppercase . R - print a string encoded in rot13 format . S - custom conversion specifier, prints string . r - prints the reversed string
/* We havent handled flags and length and precision modifiers yet. Working on it*/