Functions

In the context of programming languages, the term function means an assemblage of statements used for computing an output value. The word is used less strictly than in mathematics, where it means a set relating input variables uniquely to output variables. Functions in C or C++ programs may not produce consistent outputs for all inputs, may not produce output at all, or may have side effects. Functions can be understood as user-defined operations, in which the parameters of the parameter list, if any, are the operands.

This section discusses the following topics:

• Function declarations and definitions
• Function storage class specifiers
• Function specifiers
• Function return type specifiers
• Function declarators
• Function attributes
• The main() function
• Function calls
• Default arguments in C++ functions (C++ only)
• Pointers to functions