java - 局部变量的值没有被使用？不应该是这样吗？

Question

好吧，我正在制作一个简单的用户输入计算器，提供加、减、乘、除的选项。当我运行该程序时，一切都很顺利，直到我按回车键希望得到我的结果......什么也没有发生。 Eclipse 给出的唯一警告是未使用局部变量answer 的值....这是我的代码:

class apples {
public static void main(String args[]) {
    System.out
            .println("To Add Press 1 , To Subtract Press 2, To Multiply Press 3, To Divide Press 4");
    Scanner sc = new Scanner(System.in);
    int i = sc.nextInt();
    double fnum, snum, answer;

    if (i == 1) {
        System.out.println("Enter Your First Number: ");
        fnum = sc.nextDouble();
        System.out.println("Enter Your Second Number");
        snum = sc.nextDouble();
        answer = fnum + snum;
    } else if (i == 2) {
        System.out.println("Enter Your First Number: ");
        fnum = sc.nextDouble();
        System.out.println("Enter Your Second Number");
        snum = sc.nextDouble();
        answer = fnum - snum;
    } else if (i == 3) {
        System.out.println("Enter Your First Number: ");
        fnum = sc.nextDouble();
        System.out.println("Enter Your Second Number");
        snum = sc.nextDouble();
        answer = fnum * snum;
    } else if (i == 4) {
        System.out.println("Enter Your First Number: ");
        fnum = sc.nextDouble();
        System.out.println("Enter Your Second Number");
        snum = sc.nextDouble();
        answer = fnum / snum;
    }
}

}

Answer 1

您可以在末尾添加此内容:

System.out.println(ans)

(我会把它放在评论中，但我没有代表)