java實現計算器功能

• 寫四個方法：加減乘除

• 利用迴圈+switch進行使用者互動

• 傳遞需要操作的兩個數

• 輸出結果

public class Demo05 {
  public static void main(String[] args) {
    while (true) {
      Scanner scanner = new Scanner(System.in);
      System.out.println("請輸入第一個數字：");
      int a = scanner.nextInt();
      System.out.println("要進行的運算是：");
      String s = scanner.next();
      System.out.println("請輸入第二數");
      int b = scanner.nextInt();
//       scanner.close();
      switch (s) {
        case "+":
          System.out.println("結果是：" + add(a, b));
          break;
        case "-":
          System.out.println("結果是：" + reduce(a, b));
          break;
        case "*":
          System.out.println("結果是：" + mul(a, b));
          break;
        case "/":
          System.out.println("結果是：" + div(a, b));
          break;
​
       }
     }
   }
  public static int add(int a,int b){
    return a+b;
   }
  public static int reduce(int a,int b){
    return a-b;
   }
  public static int mul(int a,int b){
    return a*b;
   }
  public static int div(int a,int b){
    return a/b;
   }
}