printf

Write your own printf function.

Welcome

A rebuild of the standard printf function in C. Our project required a function capable of printing with the %d, %c, %s, and %% specifiers to standard output. printf returns the number of characters printed (excluding the null byte at the end of strings). We were not asked to handle flag characters, field width, precision, or length.

The Holberton Way

Holberton students rarely rely on the C standard library, instead building our own functions and headers as we learn. Here you will see a variety of our builds put to use to build a simple re-imagining of printf.

The Beast that is printf

It was daunting to approach a reinvention of printf. This is possibly the most refined function in C, with human hours spent on it thought to surpass a decade.

Format Specifiers

Our team chose to add %x ,%X, %b, %o, %u, %r, %R, and %p formatting. We relied on the library we have been building at Holberton as well as new concepts gathered during this project.

Supported Format Types

Type	Output
c	single character
s	string
r	string in reverse
R	string in rot13
d	integer in decimal
i	integer
%	percent sign
x	lowercase hex
X	uppercase hex
b	binary
o	octal
u	unsigned
p	pointer
F	expletive

Examples

Character: printf("%c", 'A'); Output:: A

String: printf("%s", 'This is a string.'); Output: This is a string.

Integer: printf("%i", 5); Output: 5

Expletive: printf("%F", anything); Output: FUCK

Deployment

This project was released soon after COVID - 19 precautions were adopted at our Holberton campus, so Cynthia and I worked both remotely and in person in our private homes for the duration. We set up a Trello board, divided tasks, and kept each other on the same page as we went.

Built With

• Ubuntu
• GitHub
• StackEdit

Project Requirements

• Allowed editors: vi, vim, emacs
• All your files will be compiled on Ubuntu 14.04 LTS
• Your programs and functions will be compiled with gcc 4.8.4 using the flags -Wall -Werror -Wextra and -pedantic
• All your files should end with a new line
• A README.md file, at the root of the folder of the project is mandatory
• Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl
• You are not allowed to use global variables
• No more than 5 functions per file
• In the following examples, the main.c files are shown as examples. You can use them to test your functions, but you don’t have to push them to your repo (if you do we won’t take them into account). We will use our own main.c files at compilation. Our main.c files might be different from the one shown in the examples
• The prototypes of all your functions should be included in your header file called holberton.h
• Don’t forget to push your header file
• All your header files should be include guarded
• Note that we will not provide the _putchar function for this project

Prototype

#include "holberton.h"

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

Compilation

gcc -Wall -Werror -Wextra -pedantic *.c

Return Value

• The number of characters printed.

Authors

• Cynthia Taylor - @wholockwars
• Tabitha O'Melay - @tabby__katz

License

This project is licensed under the Holberton School Software Engineering Program.

Acknowledgments

• The Framework
• Cohort 11
• Holberton's CPO, Poppy