0x11. C - printf

• Writing our own printf function, this is a project done under ALX Low Level Programming.

Resource

• secrets of printf
• Implementing printf and scanf in C
• All About Printf

Description

• The function _printf writes output to stdout. The function writes under the control of a format string that specifies how subsequent arguments (accessed via the variable-length argument facilities of standard library stdarg) are converted for output.

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

Return

• Upon success, _printf returns the number of characters printed (excluding the terminating null byte used to end output to strings). If an output error is encountered, the function returns -1.

Format of the Argument String

• The format string argument is a constant character string composed of zero or more directives: ordinary characters (apart from %) which are copied unchanged to the output stream; and conversion specifications, each of which results in fetching zero or more subsequent arguments.
• Conversion specification is introduced by the character % and ends with a conversion specifier (which in whole make up the format specifier.)

General Requirements

• All your files will be compiled on Ubuntu 20.04 LTS using gcc, using the options -Wall -Werror -Wextra -pedantic -std=gnu89
• All your files should end with a new line.
• No more than 5 functions per file.
• You are not allowed to use global variables.
• The prototypes of all your functions should be included in your header file called holberton.h
• All your header files should be include guarded.

Authorized functions and macros

• write (man 2 write)
• malloc (man 3 malloc)
• free (man 3 free)
• va_start (man 3 va_start)
• va_end (man 3 va_end)
• va_copy (man 3 va_copy)
• va_arg (man 3 va_arg)

Github

• There should be one project repository per group. If you clone/fork/whatever a project repository with the same name before the second deadline, you risk a 0% score.

Compilation

• The code can be compiled like this:

   gcc -Wall -Werror -Wextra -pedantic -std=gnu89 test/main.c *.c -o print

• All test files will be in the test directory.

Authors

• iAmG-r00t 👾
• Michael Ndula @Michaelndula 👨‍💻

Tasks

0. I'm not going anywhere. You can print that wherever you want to. I'm here and I'm a Spur for life : A function that produces output according to a format.

   • Prototype: int _printf(const char *format, ...);
   • Returns: the number of characters printed (excluding the null byte used to end output to strings)
   • write output to stdout, the standard output stream
   • format is a character string. The format string is composed of zero or more directives. See man 3 printf for more detail. You need to handle the following conversion specifiers:
     • c
     • s
     • %
   • You don’t have to reproduce the buffer handling of the C library printf function.
   • You don’t have to handle the flag characters.
   • You don’t have to handle field width.
   • You don’t have to handle precision.
   • You don’t have to handle the length modifiers.

1. Education is when you read the fine print. Experience is what you get if you don't : Handle the following conversion specifiers:

   • d
   • i
   • You don’t have to handle the flag characters.
   • You don’t have to handle field width.
   • You don’t have to handle precision.
   • You don’t have to handle the length modifiers.

2. Just because it's in print doesn't mean it's the gospel : Create a man page for your function.

   • How to read the man page: man ./man_3_printf