The header file <stdio.h> defines a number of functions to format and output values.

###### Character and string I/O functions

> getchar — read a character from standard input
> gets — read a string from standard input
> putchar — write a character to standard output
> puts — write a string to standard output

###### Formatted input functions

> scanf — read formatted text from standard input
> sscanf — read formatted text from a string
> vscanf — read formatted text from standard input using a va_list argument
> vsscanf — read formatted text from a string using a va_list argument

###### Formatted output functions

> printf — write formatted text to standard output
> snprintf — write formatted text to a string with truncation
> sprintf — write formatted text to a string
> vprintf — write formatted text to standard output using a va_list argument
> vsnprintf — write formatted text to a string with truncation using a va_list argument
> vsprintf — write formatted text to a string using a va_list argument