🚀 1337 Project: ft_printf

Development repository for the 42cursus' ft_printf project
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📖 About · 🔗 Useful Links

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🏆 Project Score

✅ I achieved a perfect score of 100/100 on this project! 🎯

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🗣️ What is printf?

The printf function (short for print formatted) constructs and displays strings by integrating multiple values based on a specified format.

printf("The value is %d\n", counter);

A format specifier is a special sequence beginning with %, defining how a value should be formatted:

Specifier	Description
%d	Signed integer (decimal)
%i	Signed integer (interprets octal/hex in scanf)
%s	String
%c	Character
%p	Memory address (hexadecimal)
%u	Unsigned decimal integer
%x	Hexadecimal (lowercase)
%X	Hexadecimal (uppercase)
%%	Prints a literal %

🔍 Difference Between %i and %d

In scanf:

• %d treats 012 as decimal 12
• %i interprets 012 as octal 10

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⚙️ Variadic Functions

A variadic function allows an undefined number of arguments.

📌 va_list Structure

typedef struct {
    unsigned int gp_offset;
    unsigned int fp_offset;
    void *overflow_arg_area;
    void *reg_save_area;
} va_list[1];

• reg_save_area → Pointer to the start of saved registers
• overflow_arg_area → Pointer to stack arguments
• gp_offset → Offset to next general-purpose register (default: 48)
• fp_offset → Offset to next floating-point register (default: 304)

🔹 Key Points:

• va_list is sometimes just char*
• va_arg(ap, TYPE) reads memory as TYPE
• There's no way to determine the length of a va_list

🔧 Key Macros for va_list

Macro	Description
va_start(ap, last)	Initializes ap before use
va_arg(ap, type)	Retrieves the next argument in the list
va_end(ap)	Cleans up va_list
va_copy(dest, src)	Copies va_list

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🏗️ Macros in C

A macro is a preprocessor directive (#define) that replaces code segments with predefined values.

🔹 Example

#define PI 3.14

🔍 Types of Macros

Type	Description
Object-like	Replaces a value or code segment
Function-like	Acts like a function with arguments
Chain-like	Uses macros inside other macros

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🛠️ How to Use

This project includes a Makefile to easily compile the library.

🔹 Compilation

Run the following command to compile the library:

make

This will generate the libftprintf.a archive file.

🔹 Usage in Your Code

To use ft_printf in your project, include the header and link the library:

#include "ft_printf.h"

Compile your program with:

gcc main.c libftprintf.a -o my_program

🔹 Cleaning

To remove object files and binaries:

make clean   # Removes object files
make fclean  # Removes object files and library
make re      # Cleans and recompiles everything

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📌 Useful Links

📚 Documentation & References

• C++ Reference - printf
• MacOS documentation - printf
• C Reference - Register
• C Microsoft Documentation - Variadic Functions

🛠 Technical Articles & Papers

• Secrets of printf (PDF)
• How does printf work?
• Variadic Function in C
• Printing Floating-Point Numbers

Happy coding! 🚀