/*
 **************************************************************************
 * Program name : 037_Exponentiation(Recursion) (Version 1.00)            *
 * Author       : Duck Wong                                               *
 * Language     : C / C++                                                 *
 * Compiler     : Boodshed Dec-C++ compiler Ver 3.95                      *
 * Computer     : PII350                                                  *
 * O/S          : Windows 98                                              *
 **************************************************************************
 * Version 1.00 : 2000/06/25 - first version                              *
 **************************************************************************
 * Description  : (a) input the valus of base amount                      *
 *                (b) input the value of exponent                         *
 *                (c) find the result by "for" loop                       *
 *                (d) find the result by "while" loop                     *
 *                (e) try again ?                                         *
 **************************************************************************
*/
#include <iostream.h>
#include <stdlib.h>

float Exp(float Baseamount, int Topower)
{
 float Result;

 if (Topower == 1)
   Result = Baseamount;
 else Result = Baseamount*(Exp(Baseamount, Topower-1));
 return Result;
}

int main()
{
 // part 1 : declaration
 float Baseamount, Result;
 int   Topower, Index;
 char  again;

 do {
     // part 2 : Repeat asking the valus of base amount
     do {
         cout << "Please input the base amount: ";
         cin  >> Baseamount;
         if (Baseamount<=0)
           cout << "The base amount must be greater than zero (o)\n";
         cout << "\n";
        } while (Baseamount<=0);                                     // Note (1)

     // part 3 : Repeat asking the value of exponent
     do {
         cout << "Please input the exponent: ";
         cin  >> Topower;
         if (Topower<=0)
           cout << "The exponent must be greater than zero (o)\n";
         cout << "\n";
        } while (Topower<=0);                                        // Note (2)

     // part 4 : Find the result
     Result = Exp(Baseamount,Topower);
     cout << "The value of " << Baseamount
          << " to the power " << Topower
          << " is " << Result << "\n\n";

     // part 5 : try another number ?
     cout << "\aTry another number (Y/N) : ";
     cin  >> again;
     cout << "\n";
    } while (again=='Y' || again=='y');
 cout << "\n" << endl;

 system("PAUSE");
 return 0;
}

/* Notes
   (1) This program does not support negative number.
   (2) Any number to the power zero is ONE.
       This program only works for these exponent is positive integer.
*/