Variable-length argument length

Is when we have functions that have unspecified number of arguments (eg. int printf(const char *format, ...);)
We must use variable argument headers stdarg.h.
We must use the following macros va_start, va_arg, va_list, va_end.

Command line arguments

int main(int argc, char * argv[]){} argc is the number of arguments, argv is a list of pointers to strings. (eg. ./program arg1 arg2 → argc == 3, argv == {“./program”, “arg1”, “arg2“})

Redirect input into program uses the redirect input symbol < (eg. sum < input)
Normally program output is displayed in screen, redirection grabs said input and sends it somewhere else.
Redirecting output into another program uses the pipeline symbol | (eg. random | input)
Redirect output into program uses the redirect output symbol > (eg. hello > out)
Redirect output appending it to another program using the append output symbol >> (eg. hello >> out)

rb	Read an existing file
wb	Create binary file for writing. Discards current content if file exists
ab	Appends content to end of file. Open or create file in binary format.
rb+	Open existing binary file for reading and writing
wb+	Create binary file for update. Discards current content if file exists
ab+	TODO

You will need the stdlib.h module.
You can use the atexit function to register a function upon a successful termination program
takes an argument which is a pointer to a function with no arguments

the volitile type qualifier may indicate that the variable may be changed by another program or by the computer’s hardware

Specifying the types of integer and floating-point constants:
- u or U for an unsigned integer
- l or L for a long integer
- ul, lu, UL or LU for an unsigned long integer

Integer constant is not suffixed, its type is determined by the first type capable of storing a value of that size
Suffixes are
- f or F for a float
- l or L for a long double