Types of Expressions

C++ expressions are divided into several categories:

• Primary expressions. These are the building blocks from which all other expressions are formed.
• Postfix expressions. These are primary expressions followed by an operator — for example, the array subscript or postfix increment operator.
• Expressions formed with unary operators. Unary operators act on only one operand in an expression.
• Expressions formed with binary operators. Binary operators act on two operands in an expression.
• Expressions with the conditional operator. The conditional operator is a ternary operator — the only such operator in the C++ language — and takes three operands.
• Constant expressions. Constant expressions are formed entirely of constant data.
• Expressions with explicit type conversions. Explicit type conversions, or “casts,” can be used in expressions.
• Expressions with pointer-to-member operators.
• Casting. Type-safe “casts” can be used in expressions.
• Run-Time Type Information. Determine the type of an object during program execution.