This project has been created as part of the 42 curriculum by sarfreit.

Description

ft_printf is a 42 project that recreates part of the behavior of the standard printf() function.
It strengthens your skills in:

• handling variadic arguments (va_list)
• manual data formatting
• modular and clean C programming
• implementing flags and reproducing standard printf behavior

---

🧠 Objective

Implement the function:

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

This function:

• Prints formatted output to stdout
• Supports several conversion specifiers
• Returns the number of characters printed
• Reproduces the behavior of the original printf for mandatory conversions

---

🎨 Mandatory Part

✔ Implemented conversions

Specifier	Meaning	Example
%c	Character	'A'
%s	String	"Hello"
%p	Pointer (0x...) or (nil)	(nil)
%d	Signed integer	-42
%i	Signed integer	24
%u	Unsigned integer	42
%x	Hexadecimal (lowercase)	2a
%X	Hexadecimal (uppercase)	2A
%%	Prints %	%

✔ General rules

• Only write() may be used for printing
• Return value = total printed characters
• %p prints (nil) when the pointer is NULL
• Code must follow the 42 Norm

---

⭐ Bonus Part

This project implements the bonus flag set allowed by the subject:

✔ Supported flags

Flag	Description	Example	Output
+	Always show the sign	%+d, 42	+42
(space)	Leading space for positive numbers	% d, 42	42
#	Hexadecimal prefix	%#x, 255	0xff

✔ Flag rules

• If + and are both used → + wins
• # only affects %x and %X
• # does not add prefix when the number is 0

Other flags such as width, precision, -, 0, and * are not implemented.

🔍 How It Works

1. ft_printf iterates through the format string
2. When it finds %, it checks:
   • flags
   • conversion type
3. It calls helper functions depending on the type
4. It prints numbers, strings, characters, hex, and pointers manually
5. It returns the number of characters printed

---

Instructions

1. Preparation (Compiling libftprintf.a):

   make all

2. Compilation and Linking:

   # Link main_mandatory.c against libftprintf.a and libft.a
   cc -Wall -Wextra -Werror main_mandatory.c libftprintf.a -I . -L libft -lft -o test_mandatory

3. Execution:

   ./test_mandatory

4. Preparation (Compiling libftprintf.a with Bonus features):

   make bonus

5. Compilation and Linking:

   # Link main_bonus.c against the bonus libftprintf.a and libft.a
   cc -Wall -Wextra -Werror main_bonus.c libftprintf.a -I . -L libft -lft -o test_bonus

6. Execution:

   ./test_bonus

Check for memory leaks:

valgrind --leak-check=full ./test_mandatory
valgrind --leak-check=full ./test_bonus

Clean the project:

make clean
make fclean
make re

---

Resources

For this project I used the help of some GitBooks from older students, and websites like GeeksforGeeks and W3Schools.