ft_printf_42

This a project from 42 school. The aim of this project is to code our own implementation of the libc function printf.

Usage

This function is included in library called libft_printf. You will first need to create this library using the following command:
make

You will then need to create a .c file (eg. main.c), which uses the function ft_printf. Then run the following commands:

gcc -I/path/to/this/folder/inc -I/path/to/this/folder/libft/inc -c main.c
gcc -L/path/to/folder -lftprintf main.o -o a.out
./a.out

Instructions

The only functions allowed are:

• write
• malloc
• free
• exit

Features from the original printf included

• Displaying signed numbers (%d %i)
• Displaying unsigned numbers (%u)
• Displaying unsigned numbers in octal format (%o) or hexadecimal format (%x %X)
• Displaying pointers addresses (%p)
• Displaying chars and strings (%c %s)
• Complete support of floats and long floats, included DBL_MIN/MAX, LDBL_MIN/MAX, NaN and inf (%f with flags l and L)
• Management of %%
• Management of minimum field-width
• Management of the precision
• Management of the following flags: #0-+* and space
• Support of the following length flags: hh, h, l and ll

Implementation

In order to make the function as fast as the original, a buffer is used to store the characters to print. This allows to limit the number of calls to the syscall write and to avoid having to allocate memory with malloc.

Extra options added

• Management of color
  Example: the instruction ft_printf("{yellow}Hello!\n{eoc}") will output
  

• Displaying unsigned numbers in binary format (%b). You can modulate the output like so:

  • Use the flag " " in order to print the number in groups of bytes separated by a space
  • Use the flag 0 in order to add extra zeros to have a number of printed bits which is a multiple of 8

ft_printf("%b", 1234567)    >   "100101101011010000111"
ft_printf("%0b", 1234567)   >   "000100101101011010000111"
ft_printf("% b", 1234567)   >   "10010 11010110 10000111"
ft_printf("% 0b", 1234567)  >   "00010010 11010110 10000111"