Printf Project 🖨️

Hello world welcome to our personal peer project of creating a replica of the printf function in c.
The project will entail all the process used to make a custom _printf, that has the same behaviour as the C standard libray printf.
Starting point, will be using this prototype as our starting point.
int _printf(const char *format, ...);

Run the program 👣

• Below are some of the functionality and use cases of our custom _printf() All right lets dive in and have fun while at it..
• Have included a run.sh file on the repo under the test folder to run the program and also use the _printf functionality.
• For Window users you will have to use the following command to compile the code to have an executable file. gcc -g -Wall -Wextra -Werror -pedantic -std=gnu89 -o _printf There you go you have a new replica of the printf c library function.

Use Cases & Examples ☕

Basic usage: _printf("Format String", arg1, arg2, arg3, ...);

... means indefinite number of arguments.

Examples:

• Basic String: _printf("%s World\n", "Hello");
  

• Output Hello World
  

• Print Integers: _printf("Hey i am an integer [%i]\n", 34);
  

• Output: Hey i am an integer [34]
  

There is more than this two options more will be described below, some include something like b, S, p, x and X. Not to worry will discuss this later.

Return Value ✔️

Return value of the _printf() number of bytes written on the standard output upon success, -1 failure of during program execution.

Format Specifiers ⚙️

Syntax for format specifiers almost the same as the one for printf, just added a few new custom format specifiers.

_printf("%[specifier]\n", data);
...

A specifier will be used to invoke the builtin function to execute the exepected result. The format specifier is used to signal the _printf function what to do with the data passed to it for processing and formating.

Specifiers 📌

Now the fun part begins

Specifier[letters]	Example	Output
d	Signed integer -23	23
i	Signed integer 45	45
u	Usigned integer 344	344
b	Binary representation of 98	1100010
x	Hexadecimal representation of 62	3e
X	Hexadecimal_Caps representation of 62	3E
o	Octal representation 45	55
s	String of characters	Hello world
c	Characters	c
S	Non-printable chars \n	\0xA
r	Reverse string	dlrow elloh
R	Rot13 String translation	xabj
p	Memory addresses	0x34323

Dont forget that all the format specifiers should be prefixed with the % sign in order for them to work.

Here is a walk through of all the files and their functionality in the making of the printf project.

Directories && Files 📁

Name	Information	Relavant Functions
./test	Directory with all the main.c files to test the whole program	adv_main.c
main.h	Header files contiaining all the standard library files, structers and all the files prototypes	*.c
_printf.c	Starting point for the whole project which will be used to check and call all the relevant function	_prntf, _reverse_arg, digit_counter, _abs, _percent_arg
_printf_spec_func.c	Has some more specifier functions which will be called according to the format specifier passed by the user	_digit_arg, _pointer_hex_arg, _unsigned_arg, _string_arg, _char_arg
_more_printf_spec_func.c	Again some more list of all the specifier functions which are pretty self explanatory when you read them through	_low_hex_arg, _upper_hex_arg, _octal_arg, _binary_arg, _rot13_arg
_helper_func.c	Include some shortened functions which can later be called multiple times in other files and functions	get_val_ULINT, get_val_UINT, write_buffer, create_heap_mem, _isUINT
more_helper_func.c	Some more helper functions to be used all over the program files	get_converters_val, create_special_heap, digit_long_counter, _puts, _strlen
get_hex_val.c	An extension of the _custom_spec_func.c which includes functions which are in relation with it	get_hex_val, _get_base, base_len
_custom_spec_func.c	Contains all the files which make it possible for all to work with the %S function	_no_printable_arg, fill_no_printable_buff, _is_printable, _swap_func

All functions mentioned above are well desciribed inside where they are defined and what they do.

List of all the c libray used to make the project. 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).
Thanks for reading upto here have fun while at it.👋

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AUTHORS: Mk-0-wan : SplugS