字符串不能转换为int！如何在java上对扫描的int求

问题描述

我编写了这个简单的程序来求和用户写入的扫描 int，但是当我编译它，它说字符串不能转换为int".这个程序有什么问题?

I wrote this simple program to sum a scanned int written by the user, but when i compile it, it says that "string cannot be converted to int." What is wrong in this program?

import java.util.*;
public class Pr6{
      public static void main(String[] args){
      Scanner scan = new Scanner (System.in);
      int num1;
      int num2;
      int num3;
      int sum;

                  System.out.print("Please write an integer: ");
       num1 = scan.nextLine();

                  System.out.print("Please write an integer: ");
       num2 = scan.nextLine();

                  System.out.print("Please write an integer: ");
       num3 = scan.nextLine();

       sum = num1 + num2 + num3;
                  System.out.print("Total = " + sum);



        }//main
}//Pr6

推荐答案

这是你的问题

num1 = scan.nextLine();

我们看看num1是什么数据类型:

Let's look at what data type num1 is:

int num1;

scan.nextLine() 将返回一个字符串.而且你不能有 int num1 = "1"，因为它们是不同的数据类型.

scan.nextLine() will return a String. And you can't have int num1 = "1", because they are different data types.

您应该使用 scan.nextInt().它将返回一个数字.这会解决你的问题:)

You should use scan.nextInt(). It will return a number. That'll solve your problems :)

所以你会有 num1 = scan.nextInt()、num2 = scan.nextInt() 和 num3 = scan.nextInt().