字符串不能转换为int！如何在java上对扫描的int求和?

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:

int num1;