Operators and Expression.

An operator is a symbol that tells the computer to perform certain mathematical or logical manipulations operators are used in programs to manipulate data and variables. Thus usually form a part of the mathematical or logical expression.

'C' operators can be classified in to a number of categories they include,
1. Arithmetic operators.
2. Relational operators.
3. Logical operators.
4. Assignment operators.
5. Increment and decrement operators.
6. Conditional operators.
7. Bit wise operators.
8. Special operators.

An expression is a sequence of operands and operators that reduces to a single value.