A Function is a set of statements that can be used anywhere in the program. Main reason for using it is to strcuture the programmming by creating function for repetitive tasks.

    return-type function-name(parameter list)
     {
      Statements
     }

In the above syntax the "return-type" defines the data type of the value returned by the functions, the "function-name", unique name used to call a function. The "Parameters" are seperated by commas that consist of the data type along with identfiers for the parameters.

   #include<iostream.h>
   int x,y,z,a,b,r;
   addition(int a, int b)
     {
       r = a + b;
       return (r);
     }
   int main()
     {
       cout << "Enter the first integer::"; cin >> x;
       cout << "Enter the second integer::"; cin >> y;
       z = addition(x,y);
       cout << "Sum of X and Y is::" << z << '\n';
     }

   Enter the first integer::10 
   Enter the second integer::20
   Sum of X and Y is:: 30 

In the above example a function "addition()" is used to add two numbers.