import java.util.Scanner;

public class IntegerCalculator {
 /**
  * Drives the RPN (postfix) calculator for integers.  The user can enter
  * a decimal integer, which gets passed to the calculator as an operand,
  * the operations "+", "-" and "*", which also get passed to the calculator,
  * "p", which prints the stack (with the current value on the top), or
  * "q", which quits the calculator
  * 
  */
 
 public static void main (String [] args) {
   
   Scanner scan = new Scanner (System.in);
  
   RPNCalculator<MyInt> calc = new RPNCalculator<MyInt> ();

   for (;;) {
     if (scan.hasNextInt()) // If the next input is an operand
       calc.operand(new MyInt(scan.nextInt()));
     else {
       String s = scan.next();
    
    // The three operators
    if (s.equals("+") || s.equals("-") || s.equals("*"))
     calc.operation(s);    
    else if (s.equals("p")) // Print
     calc.print();
    else if (s.equals("q")) { // Quit
      System.out.println("Bye!");
      return;
    }
    
    else // Inform the user of proper input format
     System.out.println("Valid inputs are integers, and symbols +, -, *, p, and q.");
   }
  }

 }
}