二进制运算符'-'的错误操作数类型

Question

I'm getting an error message on line "Math.sqrt(Math.pow ((x2)-(x1), 2)+Math.pow((y2)-(y1), 2));" and I can't figure what the problem is.

import java.util.Scanner;
import java.lang.Object;

public class Distance

{

   public static void main(String[] args)

   { 
    Scanner scan = new Scanner(System.in);

    System.out.println ("Enter x1: ");
    String x1=scan.nextLine();

    System.out.println ("Enter y1: ");
    String y1=scan.nextLine();

    System.out.println ("Enter x2: ");
    String x2=scan.nextLine();

    System.out.println ("Enter y2: ");
    String y2=scan.nextLine();

    double distance = Math.sqrt(Math.pow ((x2)-(x1), 2)+Math.pow((y2)-(y1), 2));

    System.out.println ("The distance between the points is: "+ distance);

   }

}

Answer 1

You're subtracting String s, not int s.

Parse the String s with Integer.parseInt(x1) .

Answer 2

- does not exist for type String .

You probably entered int values that you can read doing:

int x1 = scan.nextInt();
// etc