source code kalkulator

import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Scanner;
public class Kolkulator {
 public static void main(String[] args) {
 Deque<String> stack = new ArrayDeque<String>();
 Scanner in = new Scanner(System.in);
 while (true) {
 String input = in.nextLine();
 char ch = input.charAt(0);
 if (ch == '+' || ch == '-' || ch == '*' || ch == '/') {
 double y = Double.parseDouble(stack.pop());
 double x = Double.parseDouble(stack.pop());
 double z = 0;
 switch (ch) {
 case '+': z = x + y; break;
 case '-': z = x - y; break;
 case '*': z = x * y; break;
 case '/': z = x / y;
 }
 System.out.printf("\t%.2f %c %.2f = %.2f%n", x, ch, y, z);
 stack.push(new Double(z).toString());
 } else if (ch == 'q' || ch == 'Q') {
 return;
 } else {
 stack.push(input);
 }
 }
 }
 }