| // Example 
      program 
 #include <iostream.h>
 #include <stdlib.h>
 
 double timesTwo(double num);   // function 
      prototype
 
 int main(void)
 {
 system("CLS");
 
 double number, response;
 cout<<"Please enter a number:";
 cin>>number;
 response = timesTwo(number);  //function 
      call
 cout<< "The answer is "<<response;
 return 0;
 }
 //timesTwo function
 doubel timesTwo (double num)
 {
 double answer;   //local variable
 answer = 2 * num;
 return (answer);
 }
 
 
        
        
          
            | Notice how the variable 
            in the function (num) 
            does not have the same name as the variable sent to the function (number).  
            It makes no difference what the variables are called, as long as 
            they are of the same variable type.  Variables are used in the order 
            in which they are sent to the function. |  |