This project has been created as part of the 42 curriculum by spopa.

ft_printf

Description

This project is a reimplementation of the standard C library function printf. It handles the basic cspdiuxX% conversions, mimicking the behaviour of the original.

Supported Conversions

Specifier	Description
%c	Prints a single character.
%s	Prints a string (as defined by the common C convention).
%p	The void * pointer argument has to be printed in hexadecimal format.
%d	Prints a decimal (base 10) number.
%i	Prints an integer in base 10.
%u	Prints an unsigned decimal (base 10) number.
%x	Prints a number in hexadecimal (base 16) lowercase format.
%X	Prints a number in hexadecimal (base 16) uppercase format.
%%	Prints a percent sign.

Instructions

1. Clone the repository.
2. Run make to compile the library libftprintf.a.
3. Include the header ft_printf.h in your project and link the library.

Example usage:

#include "ft_printf.h"

int main() {
    int len = ft_printf("Hello %s, number %d\n", "World", 42);
    ft_printf("Printed %d characters\n", len);
    return (0);
}

Implementation

• Algorithm: The function iterates linearly through the format string. Standard characters are written immediately to the output. When a % is encountered, a dispatcher function identifies the flag and calls the specific printing function using va_arg.
• Data Structure: va_list (from <stdarg.h>) is used to manage the variable number of arguments.
• Recursion: To print numbers (%d, %x, etc.) without buffer management (as forbidden by the subject), a recursive approach is used. This allows printing digits in the correct order directly to the standard output without memory allocation.

Resources

• To study how the variadic functions behaved i used this YT video from the channel CodeVault.
• man va_(start, arg, end)
• This tester made by Tripouille.