Mine

/*

Name: Zach Hoggard
Student No. 250611551
Email: zhoggard@uwo.ca
Section: 004
Date: February 15, 2012
 
 */

#include <iostream>
#include <cmath>

using namespace std;

int main (void)

{
    //Initialize variables
    double base(0), result(1), result_2(1);
    int x(0),y(0), h(1), product(1), exp(0), width(0), repeat(0);
    char choice (0), letter (0);
    
    while (repeat == 0)
    {
    //Display program discription, menu, and ask for the menu selection
    cout << "This program uses a switch-based menu system to select a series of options that use for-loops.\n" << "MENU\n" << "A. Use a For-Loop to calculate the factorial, x! (without using cmath)\nB. Use a For-Loop to calculate the power function (without using cmath) y = base^exp\nC. Use a Nested For-Loop to print a sine shape of characters.\nD. Exit\n\n";
    //Input menu selection
    //Verify that the menu selection is valid
        cout << "Please enter your choice: \n";
        cin >> choice;
    
     while (!((choice >= 65 && choice <= 68) || (choice >= 97 && choice <= 100)));
    
    
    
    //Convert choice into integer values
    if (choice == 65 || choice == 97) {
        x = 1;
    } else {
        if (choice == 66 || choice == 98) {
            x = 2;
        } else {
            if (choice == 67 || choice == 99) {
                x = 3;
            } else {
                x = 4;
            }
        }
    }
        
    

    
    //Execute menu option selected
    switch (x) {
            
        //Display the discription of the case and ask for positive integer
        case 1:
            cout << "You have selected ' Calculate x! '\n Please enter a positive integer:\n";
            //Input the factorial to be calculated
            cin >> product;
            
            //Verify thata the product is a positive integer
            while (!(product >= 0)) {
                cout << "Please enter a positive integer: \n";
                cin >> product;
            }
            //Calculate the factorial
            for (y = product; y >= 1; y--) {
                
                result *= y;
            }
            //Display the result of the factorial
            cout << "The value for " << product << "! is: " << result << endl;
            
            break;

        //Display the case discription and ask for base and exponent
        case 2:
            cout << "You have selected to calculate the power function y = base^exponent\nPlease enter the base: \n";
            cin >> base;
            cout << "Please enter the exponent (Integer): \n";
            cin >> exp;
            
            //Verify that the exponent is positive
            while (!(exp >= 0)) {
                cout << "The exponent should be positive. Please re-enter the exponent: \n";
                cin >> exp;
            }
            //Calcuate the exponent
            for (h = 1; h <= exp ; h++) {
                result_2 *= base;
            }
            //Display the result
            cout << "The value of " << base << " ^ " << exp << " = " << result_2 << endl;
            
            break;
        //Display the case discription and ask for character type and width of sine    
        case 3:
            cout << "You have selected to print a sine shape of characters.\nPlease enter the character you wish to use: ";
            cin >> letter;
            cout << "Please enter the width of the sine: ";
            cin >> width;
            //Make sine curve
            for (int i = 0; i <= width; i++) {
                for (int j = 0; j <= (width *sin(i*3.14159/width)); j++) {
                    cout << letter;
                }
                    cout << endl;
            }
            
            break;
            
        //End Program
        case 4:
            repeat++;
            
            return 0;
            
    }
        cout << endl;
    }
}