1.7 Functions

• A function provides a convenient way to encapsulate some computation, which can then be used without worrying about its implementation
• Function definition:

• Function definitions declare the parameter types and names, and the type of the result that the function returns ie. int power (int base, int n)
• Function definitions can appear in any order, and in one source file or several, although no function can be split between files.
• Power function exm:

• Generally use parameter for a variable named in the parenthesized list in a function definition, and argument for the value used in a call of the function
• The name used by function definition for its parameters are local to the function definition, and are not visible to any other function
• The value that function definition computes is returned to main function by the return expression
• A function need not return a value; a return statement with no expression cause control, but no useful value, to be returned to the caller
• In main function, a return value of zero implies normal termination; non-zero values implies erroneous termination condition
• Function prototype example: int power (int m, int n); expect two int arguments and returns an int
• Function prototype declaration has to agree with the definition and uses of functions parameter names are optional in a function prototype.