CSC133 Intro to CS in C++: Function Returning a Value

Sample Program: Function That Returns a Value

//  This program reads numbers and raises each number to the given power.
//  The powers are calculated by a function. The program reads numbers
//  and powers until the user enters zero.

#include <iostream.h>

//  prototype for mypower function
long mypower(int num, int exponent);

int main()
{
   int num;
   int exponent;

//  each iteration of the loop will read a number and an exponent and
//  raise the number to the exponent by calling the function
   cout << "Enter a number (enter 0 to end): ";
   cin >> num;
   while (num != 0)
   {
      cout << "To what power would you like to raise this number: ";
      cin >> exponent;

//  call the function to raise the number to the exponent, print result
//  notice that function call is part of cout statement
      cout << "The result of raising " << num << " to the " << exponent;
      cout << " power is " << mypower(num,exponent) << endl;
      cout << "Enter a number (enter 0 to end): ";
      cin >> num;
   }
   return 0;
}

//  function definition for mypower
//  the function mypower raises the first parameter to the power
//  given by the second parameter
long mypower(int num, int exponent)     // function header
{
   long result;
   int i;

   result = num;
   for (i = 1 ; i < exponent ; i++)
      result = result * num;
   return result;
}

Sample Execution

Enter a number (enter 0 to end): 2
To what power would you like to raise this number: 16
The result of raising 2 to the 16 power is 65536
Enter a number (enter 0 to end): 10
To what power would you like to raise this number: 3
The result of raising 10 to the 3 power is 1000
Enter a number (enter 0 to end): 5
To what power would you like to raise this number: 4
The result of raising 5 to the 4 power is 625
Enter a number (enter 0 to end): 0