[Iron_Cross]

#include <iostream.h>
void main()
{
    int x = 0;         // Initialize the vars to zero
    int y = 0;
    // the NOT operator just means the oposite...since 0 can mean false and 1 can be mean true
    // He's esentially saying "If x means true, make it mean false...if x means false, make it mean true"
    // In this case, it means true, because it originally meant false
    while(!x)          
    {
	// Now he's trying to figure out, what x was originally
        switch(x)
        {
	    // If x was originally 0 (which, in this particular case it was do this...
            case 0:
		// He's now initializing x to 3 and decrementing it until it reaches 1
		// esentially that is 3 times. And since y is never changed, it will 
		// output "yes" to the screen 3 times.
               for(x=3;x>0;x--)
               {
		     // he now wants to find out what y equals
                     switch(y)
                     {
			  // in this case y (look at top of page) equals 0 so the first one will output
                          case 0:
			      // "yes" will be output
                              cout<<"yes"<<endl;
                              break;
                          default:
                              cout<<"no"<<endl;
                              break;
                     }
               }
		// since y is NOT greater than 0, x does not get changed
               if(y>0)
                   x = y;
               break;
	    // this fails because x = 0;
            case 1:
                break;
	    // same here, x does not = 2;
            case 2:
                breal;
        }
	// y now equals 1
        y++;
    }
}

You can take the rest from there..that should give you some basic idea about how the code operates.