int main(int argc, char **argv) {

   do {
        /* your program */
   } while (again);

   return 0;
}

while (answer != 0)
      {
	    cout<<" MAIN MENU                           n";
	    cout<<" quit                              0 n";
		cout<<" Read in raw to input              1 n";
		cout<<" Read in 3-D raw to input          2 n";
		cout<<" Write input image to file         3 n";
		cout<<" Write 3-D output image to file    4 n";
		cout<<" Write output image to file        5 n";
		cout<<" Zoom image with pixel replication 6 n";
		cout<<" Create a histogram                7 n";
		cout<<" Do Linear Interpolation           8 n";
		cout<<" Do Bilinear Interpolation         9 n";
		cout<<" Do Trilinear Interpolation        10n";
		cout<<" Generate circle contrast detail   11n";
		cout<<" Generate square contrast detail   12n";
		cout<<" Add noise to the image            13n";	
		cout<<" Use a convolution filter          14n";
		cout<<" Put processed image into input    15n";
		cout<<" Shrink Image                      16n";
		cout<<" Use Image calculator              17n";
		cout<<" Median Filter                     18n";
		cout<<" Average Filter                    19n";
		cout<<" Unsharp Mask                      20n";
		cout<<" Bit Reduction                     21n";
		cout<<" Generate hidden image(raw array)  22n";
		//cout<<" Fast Fourier Transform            23n";
		cout<<" Generate spoke image              24n";
		cout<<" Generate line pair image          25n";
		cout<<" Use Tile filter                   26n";
		cout<<" Read in Bitmap                    27n";
		cout<<" Change Characteristic Curve       28n";

               if (1 == answer)
              {
                    func(arguments);
              }
               else if (2 == answer)
              {
                    func(arguments);
              }
//etc....
}

#include <iostream>
#include <string>
using namespace std;

float convert_money(float, float, char);
char quit;
float money;
char tax_option;
float tax_number;
bool restart();
float var_return[4];
    
int main ()   
{
    cout << "How much money do you want to convert?: ";
    cin >> money;
    cout << "Do you want to calculate tax? (y/n): ";
    cin >> tax_option;
    
    if(tax_option == 'y')
    {
           cout << "What % is the tax?: ";
           cin >> tax_number;  
    }

    convert_money(money, tax_number, tax_option);
    
    cout << "nnDo you want to restart? (y/n): ";
    cin >> quit;
    
    if(quit == 'y')
    {
            return 0;
    }
    else
    {
            system("cls");
            main();
    }
}

float convert_money (float a, float b, char c) 
{                   
      var_return[0] = (a * 0.984348);
      var_return[1] = (a / 0.984348);
   
           
      cout << "nConvert:n" << money << " CAD = " << var_return[0] << " US";
      cout << "n" << money << " US = " << var_return[1] << " CAD";
      
      if(c == 'y') 
      {
           var_return[2] = ((a * (b / 100)) + a);  
           cout << "nnTax calculation with " << b << "% tax:n";
           cout << money << " = " << var_return[2];
      }
}

if(tax_option == 'y' || tax_option == 'yes')