CODEWITHSUNDEEP
javaswingvalidation
Kanwaldeep Singh
Kanwaldeep Singh

Reputation: 39

Validation to check if coordinates for my triangle are a valid input in java which means a triangle is properly constructed

I am taking coordinates as input like below :

System.out.print("Enter the three X coordinates for Triangle (x1cord,x2cord,x3cord) :");
int x1cord = input.nextInt();
int x2cord = input.nextInt();
int x3cord = input.nextInt();
int x[] = {x1cord,x2cord,x3cord};

System.out.print("Enter the three Y coordinates for Triangle (y1cord,y2cord,y3cord) :");
int y1cord = input.nextInt();
int y2cord = input.nextInt();
int y3cord = input.nextInt();
int y[] = {y1cord,y2cord,y3cord};

shape = FillComponent.drawTriangle(x, y);

And constructing a triangle using :

Shape triangle = new Polygon(x[], y[], 3);

I want to check if user is entering valid coordinates. ---- Need help on this.

Upvotes: 1

Views: 1665

Answers (2)

gknicker
gknicker

Reputation: 5568

The coordinates form a valid triangle if the three points are not in a line (the sum of the length of any two sides must exceed the length of the remaining side).

Therefore, using your coordinate variables, here is the triangle validation logic (using java.awt.Point):

Point vertex1 = new Point(x1cord, y1cord);
Point vertex2 = new Point(x2cord, y2cord);
Point vertex3 = new Point(x3cord, y3cord);

double side1 = Math.abs(vertex1.distance(vertex2));
double side2 = Math.abs(vertex2.distance(vertex3));
double side3 = Math.abs(vertex3.distance(vertex1));

boolean valid = side1 + side2 > side3
             && side2 + side3 > side1
             && side3 + side1 > side2;

if (!valid) {
    System.out.println("The entered coordinates do not form a triangle");
}

Upvotes: 4

Anptk
Anptk

Reputation: 1123

If you are using Swing, you can write code as follows

you will get value from

String cordinate_1=text_field1.getText();

And use the following method to check whether the user input is Integer or Not

public static boolean isNumeric(String str)  
{  
 try  
    {  
     double d = Double.parseDouble(str);  
     }  
   catch(NumberFormatException nfe)  
  {  
   return false;  
   }  
return true;  
 }

Upvotes: 0

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