0x11. C - printf

Foundations - Low-level programming & Algorithm ― Hatching out
By Julien Barbier, co-founder & CEO at Holberton School
Project to be done in teams of 2 people (your team: Gabriel Vázquez, Yared Torres
Ongoing project - started 03-12-2021, must end by 03-17-2021 (in 4 days) - you're done with 0% of tasks.
Checker will be released at 03-15-2021 03:00 AM
Manual QA review must be done (request it when you are done with the project)
QA review fully automated.

Concepts

For this project, students are expected to look at these concepts:

Group Projects
Flowcharts
Approaching a Project

Background Context

Write your own printf function.

^ In this picture, Kris - Holberton HQ Staff, and Jul - Holberton HQ Staff Resources

Read or watch:

Secrets of printf
Group Projects concept page (Don’t forget to read this)
Flowcharts concept page

man or help:

printf (3)

Requirements General

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

GitHub

There should be one project repository per group. If you clone/fork/whatever a project repository with the same name before the second deadline, you risk a 0% score. More Info Authorized functions and macros

write (man 2 write)
malloc (man 3 malloc)
free (man 3 free)
va_start (man 3 va_start)
va_end (man 3 va_end)
va_copy (man 3 va_copy)
va_arg (man 3 va_arg)

Compilation

Your code will be compiled this way:

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

As a consequence, be careful not to push any c file containing a main function in the root directory of your project (you could have a test folder containing all your tests files including main functions)
Our main files will include your main header file (holberton.h): #include holberton.h
You might want to look at the gcc flag -Wno-format when testing with your _printf and the standard printf. Example of test file that you could use:

alex@ubuntu:~/c/printf$ cat main.c #include <limits.h> #include <stdio.h> #include "holberton.h"

/**

• main - Entry point

• Return: Always 0 */ int main(void) { int len; int len2; unsigned int ui; void *addr;

  len = _printf("Let's try to printf a simple sentence.\n"); len2 = printf("Let's try to printf a simple sentence.\n"); ui = (unsigned int)INT_MAX + 1024; addr = (void *)0x7ffe637541f0; _printf("Length:[%d, %i]\n", len, len); printf("Length:[%d, %i]\n", len2, len2); _printf("Negative:[%d]\n", -762534); printf("Negative:[%d]\n", -762534); _printf("Unsigned:[%u]\n", ui); printf("Unsigned:[%u]\n", ui); _printf("Unsigned octal:[%o]\n", ui); printf("Unsigned octal:[%o]\n", ui); _printf("Unsigned hexadecimal:[%x, %X]\n", ui, ui); printf("Unsigned hexadecimal:[%x, %X]\n", ui, ui); _printf("Character:[%c]\n", 'H'); printf("Character:[%c]\n", 'H'); _printf("String:[%s]\n", "I am a string !"); printf("String:[%s]\n", "I am a string !"); _printf("Address:[%p]\n", addr); printf("Address:[%p]\n", addr); len = _printf("Percent:[%%]\n"); len2 = printf("Percent:[%%]\n"); _printf("Len:[%d]\n", len); printf("Len:[%d]\n", len2); _printf("Unknown:[%r]\n"); printf("Unknown:[%r]\n"); return (0); } alex@ubuntu:/c/printf$ gcc -Wall -Wextra -Werror -pedantic -Wno-format *.c alex@ubuntu:/c/printf$ ./printf Let's try to printf a simple sentence. Let's try to printf a simple sentence. Length:[39, 39] Length:[39, 39] Negative:[-762534] Negative:[-762534] Unsigned:[2147484671] Unsigned:[2147484671] Unsigned octal:[20000001777] Unsigned octal:[20000001777] Unsigned hexadecimal:[800003ff, 800003FF] Unsigned hexadecimal:[800003ff, 800003FF] Character:[H] Character:[H] String:[I am a string !] String:[I am a string !] Address:[0x7ffe637541f0] Address:[0x7ffe637541f0] Percent:[%] Percent:[%] Len:[12] Len:[12] Unknown:[%r] Unknown:[%r] alex@ubuntu:~/c/printf$

  We strongly encourage you to work all together on a set of tests If the task does not specify what to do with an edge case, do the same as printf

Description Our _printf function writes output to stdout, the standard output. It is variadic and can, therefore, take any number of arguments. Successful execution returns the number of characters printed (minus the null byte). Unsuccessful execution produces a negative value return.

Example To print out the name and age of a person where age is of type int and name and is a pointer to a string: #include "holberton.h" _printf("My name is %s and I am %d years old\n", name, age);