_printf Project

This is a Holberton School project implementing a custom version of the C standard library printf function.

Description

The _printf function produces output according to a format string, similar to the standard printf function. It writes the output to stdout and returns the number of characters printed.

Requirements

• Allowed editors: vi, vim, emacs
• All files compiled on Ubuntu 20.04 LTS using gcc with flags: -Wall -Werror -Wextra -pedantic -std=gnu89
• All files end with a newline
• Code follows Betty style guide
• No global variables allowed
• Maximum 5 functions per file
• All function prototypes in main.h
• Header file includes guards

Compilation

gcc -Wall -Werror -Wextra -pedantic -std=gnu89 -Wno-format *.c -o printf

Files

• main.h - Header file with function prototypes and include guards
• _printf.c - Main implementation file containing the _printf function and helper functions
• man_3_printf - Manual page for the _printf function
• README.md - This file

Implemented Features

Task 1: Basic Format Specifiers

• %c - Print a character
• %s - Print a string
• %% - Print a percent sign

Task 2: Integer Format Specifiers

• %d - Print an integer in decimal
• %i - Print an integer in decimal

Task 3: Manual Page

• Created man page documentation (man_3_printf)

Function Prototype

int _printf(const char *format, ...);

Return Value

• Number of characters printed (excluding the null byte) on success
• -1 if format is NULL

Usage Example

#include "main.h"

int main(void)
{
    _printf("Hello, %s!\n", "World");
    _printf("Number: %d\n", 42);
    _printf("Character: %c\n", 'A');
    _printf("Percent: %%\n");
    return (0);
}

Notes

• This implementation does not handle buffer management like the standard printf
• Flag characters, field width, precision, and length modifiers are not supported
• For unrecognized conversion specifiers, a percent sign followed by the character is printed
• A trailing percent sign at the end of the format string is ignored

Authors

Holberton School printf implementation group