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Expressions with Unary Operators

Unary operators act on only one operand in an expression. The unary operators are as follows:

These operators have right-to-left associativity. Unary expressions generally involve syntax that precedes a postfix or primary expression.

The following are the possible forms of unary expressions.

  • postfix-expression

  • ++unary-expression

  • ––unary-expression

  • unary-operator cast-expression

  • sizeof unary-expression

  • sizeof( type-name )

  • decltype( expression )

  • allocation-expression

  • deallocation-expression

Any postfix-expression is considered a unary-expression, and because any primary expression is considered a postfix-expression, any primary expressions is considered a unary-expression also. For more information, see Postfix Expressions and Primary Expressions.

A unary-operator consists of one or more of the following symbols: * & + – ! ~

The cast-expression is a unary expression with an optional cast to change the type. For more information see Cast Operator: ().

An expression can be any expression. For more information, see Expressions (C++).

The allocation-expression refers to the new operator. The deallocation-expression refers to the delete operator. For more information, see the links earlier in this topic.

See Also

Reference

Types of Expressions