Java if语句终止而不运行

Question

我正在制作一个纯粹用于学习目的的基本计算器.这是有问题的代码块:

Scanner Operation = new Scanner(System.in);
Scanner data = new Scanner(System.in);
String add, sub, mul, div;
double fnum, snum, answer;

add = Operation.nextLine();
System.out.println(add);

if (Operation.equals("add")) {
    System.out.println("Enter the first number: ");
    fnum = data.nextDouble();
    System.out.println("Enter second number: ");
    snum = data.nextDouble();
    answer = fnum + snum;
    System.out.println("Your answer is " + answer);
}

程序要求输入和终止两个而不运行if语句.

任何帮助将非常感激.

Answer 1

Operation是你的Scanner,add是String你读到的.

这个

if (Operation.equals("add")) {

应该

if (add.equals("add")) {

但老实说,你应该选择更有意义的变量名.