ASCII stands for American Standard Code for Information Interchange. Computers can only understand numbers, so an ASCII code is the numerical representation of a character such as ‘a’ or ‘@’ or an action of some sort. Below is the ASCII character table and this includes descriptions of the first 32 non-printing characters. ASCII was actually designed for use with teletypes and so the descriptions are somewhat obscure. ASCII code uses 8 bits. A unique 7-bit integer is assigned to each character, and the extra bit is used on various computers to create a proprietary character set.
ASCII Control Characters
Character codes in the range 0 through 31 are called ASCII control characters. If a program writes these codes to standard output (as in C++), the control characters will carry out predefined actions.