Java question

[Timesobserver]

Hi all,

I decided that I haven't tortured myself enough and decided to try my hand with Java. Here's my problem:

Write an application that reads the (x,y) coordinates for two points. Compute the distance between the two points using the following formula:

Distance= squared (x2 - x1) squared + (y2-y1) squared

This is what I have so far:

(It says PHP down below but it's really Java)

import java.util.* ;   
public class distance 
{
    public static void main( String [] args )
    {
    Scanner keyboard = new Scanner( System.in) ; 
    
    double dblX1;
    double dblY1;
    double dblX2;
    double dblY2;
    
    //double dblDiffX;
    //double dblDiffY;
    
    double dblDiffX = dblX2 - dblX1;
    double dblDiffY = dblY2 - dblY1; 
    

    System.out.println("Please input x: \n" );

    double dblDiffX1 = keyboard.nextDouble() ;  

    System.out.println("Please input y: \n" );

    double dblDiffY1 = keyboard.nextDouble() ;  

    double distance = Math.sqrt( (dblDiffX - dblX2) + (dblY1 - dblDiffY));
    //double distance = Math.sqrt( dblX1 * dblX1 + dblY1 * dblY1 ) ; //sqrt() calculates the square root

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



    } //end main
    } 

I think my biggest problem is not being able to figure out the math formula. Any suggestions or help?