Unary Operators in C Programming

C includes a class of operators that act upon a single operand to produce a new value. Such operators are known as unary operators.

Unary operators usually precede their single operand, though some unary operators are written after their operand.

Unary Operators

  1. Unary Minus (-) :
    The most common unary operator is unary minus, where a numerical constant, variable, or expression is preceded by a minus sign.
    For example: -23.4, -34 etc.
  2. Increment Operator (++) :
    The increment operator causes its operand to be incremented by 1.
    This operator can be used in two ways i.e. as a post increment or pre increment.

    Post increment:
    If a = 2 then a++ causes value of a to be incremented by one i.e. after executing a++ we get value of a =3.

    Pre Increment:
    If a = 2 then ++a also causes value of a to be incremented by one i.e. after executing ++a we get value of a =3.
  3. Decrement Operator (--) :
    The decrement operator causes its operand to be decremented by 1.
    This operator can be used in two ways i.e. as a post decrement or pre decrement.

    Post Decrement:
    If a = 2 then a-- causes value of a to be decremented by one i.e. after executing a-- we get value of a =1.

    Pre Decrement:
    If a =2 then --a also causes value of a to be decremented by one i.e. after executing --a we get value of a =3.
  4. sizeof() Opearator :
    sizeof is keyword in C which is used to find size occupied by different data types in memory.

    For example:
    a. sizeof(int) gives value of 2.
    b. If we declare variable like: float x; then sizeof(x) gives 4.
  5. Logical Not (!) Operator :
    This operator reverses the meaning of condition. For example: !(False) gives True and !(True) gives False.