Concept of Data

The information a program is working on is called data, in very general term. On a basic machine level, data are represented by a sequence of binary gigits, called bits. To distinguish values associated with the same bit string, additional information is required. This is called the data type definition and describes the set of values the variable of a certain type can hold. For example, the 16 bit string $$ 0000000000110101 $$ can be Interpreted during program execution as the whole number “53” or the ASCII-character “5”. In the first case it is a variable of type INTEGER, otherwise of type CHAR.