Functions in C++

  

Functions

A function is a group of statements that together perform a task. Every C++ program has at least one function, which is main().

Defining a Function

The general form of a C++ function definition is as follows −

return_type function_name( parameter list ) {

   body of the function

}

A C++ function definition consists of a function header and a function body. Here are all the parts of a function −

·        Return Type − A function may return a value. The return_type is the data type of the value the function returns. Some functions perform the desired operations without returning a value. In this case, the return_type is the keyword void.

·        Function Name − This is the actual name of the function. The function name and the parameter list together constitute the function signature.

·        Parameters − A parameter is like a placeholder. When a function is invoked, you pass a value to the parameter. This value is referred to as actual parameter or argument. The parameter list refers to the type, order, and number of the parameters of a function. Parameters are optional; that is, a function may contain no parameters.

·        Function Body − The function body contains a collection of statements that define what the function does.

 

Types of Functions

There are two types of functions in C programming:

1. Library Functions: are the functions which are declared in the C++ header files such as ceil(x), cos(x), exp(x), etc.

2. User-defined functions: are the functions which are created by the C++ programmer, so that he/she can use it many times. It reduces complexity of a big program and optimizes the code.