package calc; public class Calculator { private static int result; // Static variable where the result is stored public void add(int n) { result = result + n; } public void substract(int n) { result = result - 1; //Bug : should be result = result - n } public void multiply(int n) { } // not ready yet public void divide(int n) { result = result / n; } public void square(int n) { result = n * n; } public void squareRoot(int n) { for (; ;) ; //Bug : loops indefinitely } public void clear() { // Cleans the result result = 0; } public void switchOn() { // Swith on the screen, display "hello", beep // and do other things that calculator do nowadays result = 0; } public void switchOff() { // Display "bye bye", beep, switch off the screen } public int getResult() { return result; } }