ft_printf - Custom Printf Implementation

Introduction

This project provides a custom implementation of the printf function, supporting the specifiers c, s, p, d, i, u, x, X, and %. It is developed as part of the printf project at Hive Helsinki Coding School, with the primary goal of learning how to work with variadic arguments using va_list.

The va_list is a type in C used to handle variable argument lists in functions. It provides a mechanism for accessing arguments of variable length in a function, typically used with the stdarg.h header. In the context of the printf implementation, va_list is used to handle variable arguments passed to the function, allowing for flexibility in the number and types of arguments.

Specifiers printers are based on the libft project functions (v1.0.0), modified to return an int instead of void. This make possible to catch -1 errors when calling write. The code is designed to be extensible, allowing for future support of different file descriptors. For now, the file descriptor is set for printing to the screen.

Contents

• Source Files:
  • ft_printf.c: Main printf implementation.
  • ft_putformat.c: Function to handle formatting based on specifiers.
  • ft_putchar_fd.c: Function to print a character.
  • ft_putstr_fd.c: Function to print a string.
  • ft_putptr_fd.c: Function to print a pointer.
  • ft_putnbr_fd.c: Function to print a number.
  • ft_putnbr_fd_uns.c: Function to print an unsigned number.
  • ft_putnbr_fd_hex.c: Function to print a hexadecimal number.

Implementation

The ft_printf function serves as the main entry point. It mimics the standard printf by parsing the format string, identifying specifiers, and printing formatted output. The implementation follows a modular design:

• ft_printf iterates through the string, printing its characters, until the end or a specifier is found.
• If a specifier is found, the ft_putformat function handles formatting based on the specified specifier and calls the corresponding printer functions.
• Specific printer functions (ft_putchar_fd, ft_putstr_fd, etc.) handle the actual printing.
• All functions return an int and handle errors during writing.

At any step of the printing process, if any error arises from the write function, ft_error_w catches the error and returns a -1 value that cascades until ft_printf and the functions exit.

Getting Started

To use this printf implementation, you must clone the repo and run the makefile

git clone https://github.com/pmarkaide/42_printf.git ft_printf
cd ft_printf
make

Call ft_printf in your code as you would with the standard printf function.

Usage Examples

#include "ft_printf.h"

int main() {
    // Example 1: Print integers
    int num = 42;
    ft_printf("Integer: %d\n", num);

    // Example 2: Print strings
    const char *str = "Hello, World!";
    ft_printf("String: %s\n", str);

    // Example 3: Print characters
    char ch = 'A';
    ft_printf("Character: %c\n", ch);

    // Example 4: Print hexadecimal number
    unsigned int hex_num = 0xA5;
    ft_printf("Hexadecimal: %x\n", hex_num);

    // Example 5: Print pointer address
    void *ptr = #
    ft_printf("Pointer Address: %p\n", ptr);

    // Example 6: Print percentage sign
    ft_printf("This is a percentage sign: %%\n");

    return 0;
}

Contribution Guidelines

Contributions to this printf implementation are welcome! If you find any bugs, feel free to open an issue.

License

This project is licensed under the MIT License.