Temperature Converter

/*
**      Filename:   Temp.mash
**      Author:     Thanasi Poulos
**      Purpose:    Converting temperatures
*/

import console;
int bigloop = 1;
int selection = 0;

   while(selection == 0){
      println("+------------------------+");
      println("| TEMPERATURE CONVERTER! |");
      println("|          -BY-          |");
      println("|     THANASI POULOS     |");
      println("|                        |");
      println("| 1. C -> F              |");
      println("| 2. F -> C              |");
      println("| 3. C -> K              |");
      println("| 4. K -> C              |");
      println("| 5. F -> K              |");
      println("| 6. K -> F              |");
      println("| 7. EXIT                |");
      println("+------------------------+");
      print  ("Make a selection: ");
      selection = readInt();

   while (selection == 1){
      print("Enter degrees C to convert to degrees F: ");
      double c=readDouble();
      println();
      double f=(c*9/5)+32;
      println(c + " degrees celcius equals " + f + " degrees fahrenheit.");
      println();
      print("Type \"menu\" to return to the main menu or \"exit\" to close the program: ");
      String response = readWord();
      String compare = "menu";
      boolean menu = equals(response, compare);
      if (menu == true){
           selection = 0;
         }else{
           selection = 7;
         }
      }
   while (selection == 2){
   print("Enter degrees F to convert to degrees C: ");
      double f = readDouble();
      println();
      double c = (f-32)*(5.0/9.0);
      println(f + " degrees farenheit equals " + c + " degrees celcius.");
      println();
      print("Type \"menu\" to return to the main menu or \"exit\" to close the program: ");
      String response = readWord();
      String compare = "menu";
      boolean menu = equals(response, compare);
      if (menu == true){
           selection = 0;
         }else if (menu == false){
            selection = 7;
         }
      }
    while (selection == 3){
    print("Enter degrees C to convert to degrees K: ");
      double c = readDouble();
      println();
      double k = c + 273.15;
      println(c + " degrees celcius equals " + k + " degrees kelvin.");
      println();
      print("Type \"menu\" to return to the main menu or \"exit\" to close the program: ");
      String response = readWord();
      String compare = "menu";
      String compare2 = "exit";
      boolean menu = equals(response, compare);
      if (menu == true){
           selection = 0;
         }else{
            boolean exit = equals(response, compare2);
            if (exit == true){
               selection = 7;
            }else{
               println("Incorrect Parameter.");
               selection = 7;
            }
         }
      }
   }