Ft_Printf

This is a custom implementation of the C library function printf for the 42 programming curriculum. The ft_printf function is used to format and print text to the console.

Usage

To use ft_printf, simply call the function with a format string and any arguments you want to print. The format string can contain conversion specifiers, which are placeholders that tell ft_printf how to format the arguments.

For example:

#include "ft_printf.h"

int main(void)
{
    ft_printf("Hello, %s!\n", "world");
    return 0;
}

This will print Hello, world! to the console.

Available Conversion Specifiers

ft_printf supports the following conversion specifiers:

Specifier	Description
%c	Print a single character
%s	Print a string
%d	Print a signed decimal integer
%i	Print a signed decimal integer
%u	Print an unsigned decimal integer
%o	Print an unsigned octal integer
%x	Print an unsigned hexadecimal integer (lowercase)
%X	Print an unsigned hexadecimal integer (uppercase)
%p	Print a pointer
%%	Print a literal % character

Printf() as a Variadic Function in C

A variadic function is a function in C that accepts a variable number of arguments. This is achieved using the ellipsis (...) syntax in the function declaration. Printf() is a variadic function by nature because the function doesn't know at compile time how many arguments it will be given. Thus, we must use a variadic function prototype and #include the stdarg.h library when creating our own ft_printf() function. For example:

int sum(int count, ...);

The ellipsis syntax allows the function to accept any number of arguments after the fixed arguments. To access the variable arguments inside the function, we use the stdarg.h header and the functions defined within it. The most commonly used functions are:

• va_start() - initializes a va_list object to point to the first argument after the fixed arguments
• va_arg() - retrieves the next argument of a specified type from the va_list object
• va_end() - frees any resources associated with the va_list object

Here's an example of a variadic function that accepts a variable number of integers and returns their sum:

#include <stdarg.h>
int sum(int count, ...)
{
int i;
int sum;
va_list args;
va_start(args, count);
sum = 0;
i = -1;
while(++i < 3)
{
sum += va_arg(args, int);
}
va_end(args);
return sum;
}

In this example, we first initialize a va_list object named args using va_start(). We then loop through the specified number of arguments and use va_arg() to retrieve each argument as an integer and add it to the sum variable. Finally, we free any resources associated with the va_list object using va_end().

Variadic functions are commonly used in C libraries that need to accept a variable number of arguments. The printf() and scanf() functions, for example, are variadic functions that are used to format and print input and output.