为什么这总是被评价为假的？[副本]

Question

这是一个简单的程序，生成0到1000之间的两个随机数，然后让用户输入两个数字的和。即使您输入了正确的答案，并且求和与答案匹配，if语句也总是计算为不正确。

import java.util.Random;
import java.util.Scanner;

public class mathquiz
{
    public static void main(String[] args)
    {
        Integer num1;
        Integer num2;
        Integer sum;
        Integer answer;
        Scanner input = new Scanner(System.in);
        Random rand = new Random();
        num1 = rand.nextInt(1000); //random number between 0 and 1000
        rand = new Random();
        num2 = rand.nextInt(1000); //random number between 0 and 1000
        System.out.println("  "+num1); 
        System.out.println("+ "+num2);
        sum = num1 + num2; //adding the two random numbers together
        answer = input.nextInt();
        System.out.println(sum); //test print to see what sum is
        System.out.println(answer); //test print to see what answer is
        if (sum == answer) //always evaluates as incorrect, I would like to know why
        System.out.println("Congratulations! You are correct!");
        else
        System.out.println("You were incorrect. The correct answer is: "+sum);
    }
}

Answer 1

sum.equals(answer)可能会给出您想要的结果。