printf

Description

The _printf function emulates functionality of the C standard library function printf, writing output to standard output.
The function uses a string format where the data to print is indicated, followed by the arguments to be printed (_printf use variadic functions to allow a custom number of arguments).

Prototype: int _printf(const char *format, ...);

Return Value: if the function is executed correctly, it returns the number of characters printed (not counting the null character). If something goes wrong, it returns -1.

Use

General call of _printf function:
_printf("format", var1, var2, ...);

Examples:

• String without arguments: _printf("Let's try to printf a sentence.");
  • Output: Let's try to printf a sentence.
• Basic use with string and char specifier: _printf("%s%c", "I am a string", '!');
  • Output: I am a string!
• Print some numbers: _printf("the square root of %i is %d", 15625, 125);
  • Output: the square root of 15625 is 125

In this way you can use and mix different specifiers accepted by the _printf function.

Specifiers

Specification characters are the main component of the _putchar function. The char '%' is used followed by a character that indicates the type of data to be printed. The specification character is placed in the format string and the data to be printed is placed as an argument of the function.

Specifier	Description
%c	Prints a character.
%s	Prints a string.
%r	Prints a string in reverse.
%R	Prints a string in rot13 encryption.
%i or %d	Prints an int number.
%u	Prints an unsigned int number.
%b	Prints an unsigned int number in binary notation.
%o	Prints an unsigned int number in octal notation.
%x	Prints an unsigned int number in hexadecmal notation (lowercase).
%X	Prints an unsigned int number in hexadecmal notation (uppercase).
%%	Prints the '%' char.

Compilation

The _printf function was coded on an Ubuntu 14.04 LTS machine with gcc version 4.8.4.

The code compile with gcc -Wall -Werror -Wextra -pedantic *.c command, also it's necessary add a main file that calls the function.

Files

• holberton.h
• _printf.c
• _putchar.c
• print_str.c
• print_num.c
• print_hex.c
• print_rot13.c
• man_3_printf
• test/
  • test_collection

Authors

Maximiliano Pan & Rodolfo Delgado.