Determine If Two Points Are Near

Question

I have the following: ``` bool AreNear(Point Old, Point Current) { int x1 = Convert.ToInt32(Old.X); int x2 = Convert.ToInt32(Current.X); int y1 = Convert.ToInt32(Old.Y); int y2 = Convert.ToInt32(Current.Y); if (x1 == x2) { if (y1 == y2) { return true; } } return false; } ``` I want to return true in the function if the current point is in 25 pixels radius of the old point. Can anyone tell me how to do that?

Accepted Answer

You can use the Pythagorean formula to calculate the distance between two points. In C#:

```
var d = Math.Sqrt(Math.Pow(x1 - x2, 2) + Math.Pow(y1 - y2, 2)) 
```

Why does this work? Have a look at the following diagram and remember that `a^2 + b^2 = c^2` holds for right triangles:

Determine If Two Points Are Near

Solution

Problem