java - 在 Java 中生成随机数学运算符

Question

我想知道我应该如何从 switch 语句中初始化 int c。我不知道如何将随机开关参数“提取”到最终答案中。我是初学者，所以也许我在这里遗漏了一些明显的东西。这是我到目前为止的代码:

import java.util.*;
public class whileTest{
public static void main (String args[]){
    Scanner sc = new Scanner(System.in);

    String a;

        do{

        String operatorSwitch;
        int b;
        int c;

        Random number = new Random();
        int d = number.nextInt(100) +1;
        int e = number.nextInt(100) +1;

        Random operatorChoice = new Random();
        int operator = operatorChoice.nextInt(4);

        switch (operator){

            case 0: operatorSwitch= "+";
                c = d+e;
                break;
            case 1: operatorSwitch= "-";
                c = d-e;
                break;
            case 2: operatorSwitch= "*";
                c = d*e;
                break;
            case 3: operatorSwitch= "/";
                c = d/e;
                break;
            default: operatorSwitch= "";
        }
        System.out.println("What is: "+d+operatorSwitch+e+"?");
        b = sc.nextInt();


        if(b!=c)
            System.out.println("Wrong answer! Right answer is: "+c);
        else{if(b==c)
            System.out.println("Right answer!"+c);
        }
            System.out.println("Continue? y/n");
            a = sc.next();

        }while(a.equals("y"));
    }
}

Answer 1

作为一种实践，除非您有充分的理由不这样做，否则您应该始终明确地初始化您的变量。在这种情况下你想改变这个:

String operatorSwitch;
int b;
int c;

对此:

String operatorSwitch = null;
int b = 0;
int c = 0;

您当前代码的问题是编译问题，因为变量“c”可能没有被初始化。