package calc; public class Calculator { PRivate static int result; //存儲(chǔ)結(jié)果的靜態(tài)變量 public void add(int n) { result = result + n; } public void substract(int n) { result = result - 1; //錯(cuò)誤：應(yīng)該是"result = result - n" } public void multiply(int n) {} //還沒實(shí)現(xiàn) public void divide(int n) { result = result / n; } public void square(int n) { result = n * n; } public void squareRoot(int n) { for (; ;) ; //錯(cuò)誤：無限循環(huán) } public void clear() { //清除結(jié)果 result = 0; } public void switchOn() { //打開屏幕，顯示"hello"，并報(bào)警 result = 0; //實(shí)現(xiàn)其它的計(jì)算器功能 } public void switchOff() { } //顯示"bye bye"，報(bào)警，并關(guān)閉屏幕 public int getResult() { return result; } } 二、 遷移一個(gè)測(cè)試類
