ft_printf

This project has been created as part of the 42 curriculum by ferde-so.

Description

ft_printf is a custom implementation of C's printf function of the libc library in stdio.h header.

The main goal of this project is to learn how to use functions with a variable number of arguments (variadic functions) using the quartet: va_start, va_arg, va_copy, and va_end.

Instructions

After cloning or downloading the repository, compile and use the library like this:

1. Open a terminal in the ft_printf directory.
2. Run make to build the library archive libftprintf.a.
3. Link libftprintf.a with your own C programs by adding -L . -lft to the compilation command.

-L /path/ : Directs the linker where to search for your custom binary libraries.

-l[name] : Links a specific library (e.g., -lfoo looks for libfoo.a or libfoo.so).

Example:

make
cc -Wall -Wextra -Werror main.c -L. -lftprintf -o my_program

or, simply:

make
cc -Wall -Wextra -Werror main.c libftprintf.a -o my_program

To clean build files:

make clean

To remove compiled objects and the library:

make fclean

To rebuild everything from scratch:

make re

Resources

References used during development:

• C standard library documentation (man printf).
• The 42 Network project pdf's.
• Online C learning resources such as w3schools.com, geeksforgeeks.org, stackoverflow.com, etc.
• Github for automatic testers (printfTester).

AI usage:

• AI assistance was used in many instances, from discussion of topics, errors, ideas, problems, and improvements, to explanations, research, tests, and to help draft and write the README content.

• But mostly to search for learning resources and to explain problems in the code (e.g., "Why doesn't it work?", "What is the difference between x, y, and z?", etc.).

Description of the library

The structure is a simple read character by character of the string given, printing characters and testing for the many conditions for special printing when finding a % character and the following character being in the set cspdiuxX% or not:

• %c — prints a single character.
• %s — prints a string (as defined by the common C convention).
• %p — the void * pointer argument is 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.

This is done using these functions:

• ft_char_in_set — checks if a character is in a set of characters.
• ft_printf — the main function created to call the others. Returns the sum of the printed characters.
• ft_putchar — writes a character to the standard output and returns 1.
• ft_puthex — writes a hexadecimal number to the standard output and returns its length.
• ft_putnbr — writes an integer number to the standard output and returns its length.
• ft_putptr — writes a hexadecimal pointer number to the standard output and returns its length.
• ft_putstr — writes a string to the standard output and returns its length.
• ft_putunbr — writes an unsigned integer number to the standard output and returns its length.