Thread: Program not working - help?

So this is one of the practice questions for my computer science exam tomorrow. For some reason, whatever numbers I enter, the result comes up with this:

Enter y2:
5
Enter y1:
2
Enter x2:
4
Enter x1:
2
The solution to the equation (y2-y1) / (x2 - x1) is NaN.

Why is the answer always NaN? Someone tell me what I'm doing wrong? Here is the code:

import java.io.*;
 
class questionone
{
 
 
 
    public static void main (String [] args) throws IOException
    {
        InputStreamReader inStream = new InputStreamReader (System.in);
        BufferedReader stdin = new BufferedReader (inStream);
 
        double y2;
        double y1;
        double x2;
        double x1;
 
        System.out.println ("Enter y2:  ");
        y2 = Double.parseDouble (stdin.readLine ());
 
        System.out.println ("Enter y1:  ");
        y1 = Double.parseDouble (stdin.readLine ());
 
        System.out.println ("Enter x2:  ");
        x2 = Double.parseDouble (stdin.readLine ());
 
        System.out.println ("Enter x1:  ");
        x1 = Double.parseDouble (stdin.readLine ());
 
        Calculations calculate = new Calculations (x1, x2, y1, y2);
 
 
 
        System.out.println (calculate.receive());
 
    }
}
 
 
class Calculations
{
 
 
    double x1;
    double x2;
    double y1;
    double y2;
 
    Calculations (double x1, double x2, double y1, double y2)
    {
        this.x1 = x1;
        this.x2 = x2;
        this.y1 = y1;
        this.y2 = y2;
    }
 
 
    double numerator = y2 - y1;
    double denominator = x2 - x1;
    double solution = numerator / denominator;
 
    String receive ()
    {
        return ("The solution to the equation (y2-y1) / (x2 - x1) is  " + solution + ".");
    }
 
}

Thanks

So what could I do to make it work?

I got it working. Thanks for the help!

Post your wwwwwwworkin' code for those who might have your same problem