C++ Functions

Below are some of the features of a C++ function

• Every C++ program has at least one function and is known as the main(), and all other trivial programs can define additional functions. 
• A function is a group of statements that perform tasks together. 
• The declaration of a function instructs the compiler about a function's name, return type, and parameters. 
• The definition of a function provides the actual body of the function. Functions are known by various names like a method or a sub-routine or a procedure, and so on. 
• During programming, codes can be divided up into separate functions. However how functions are divided depends on the programmer, but logically, the division is such that each function performs a specific task. 

Syntax:

return_type function_name( parameter list ) 

{ 

    body of the function 

}

The definition of a C++ function typically consists of a function header and a function body. These parts of a function are listed and described below: 

Return Type: 

A function may be used to return a value. The return type function returns the data type of the value of the function. However, some functions perform such operations without returning a value. So, therefore, the return type is the keyword void. 

Function Name: 

These indicate the true name of the function. In addition, the function name and the parameter list, both constitute the function signature. 

Parameters: 

During programming, once a function is invoked, a value is passed to the parameter. Hence, this value could be referred to as the true parameter or argument. However, the parameter list refers to the data type, order, and a number of parameters of a function. 

Though, parameters are optional. This means that functions may not contain any parameter.

Function Body: 

This function typically contains a collection of statements that define the actual thing the function does.

Example:

#include <iostream>
 
// function declaration
int max(int num1, int num2);
 
int main ()
{
// local variable declaration:
int a = 99;
int b = 97;
int ret;
 
// calling a function to get max value.
ret = max(a, b);
 
cout << "Max value is : " << ret << endl;
 
return 0;
}
 
// function returning the max between two numbers
int max(int num1, int num2) 
{
// local variable declaration
int result;
 
if (num1 > num2)
result = num1;
else
result = num2;
 
return result; 
}