A class that illustrates how to determine if a point falls on a line

gistfile1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace PointOnLine
{
    class Class1
    {

        public static void Main()
        {
            PointLine(2,2,4,2,5,2);
        }

        private static bool PointLine(float x1, float y1, float x2, float y2, float x, float y)
        {

            bool OnLine = false;                    //returnValue
            
            if (x1 == x2) //this means it is a vertical line, avoid the Divide by Zero error.
            {
                if (Math.Abs(x - x1) <= .001)
                    OnLine = true;
                else
                    OnLine = false;

            }
            else
            {
                //given two points create the linear equation in the form of y=mx+b

                double m = (y1 - y2) / (x1 - x2);   //slope
                double b = y1 - m * x1;             //y-intercept

                if (Math.Abs(y - (m * x + b)) <= .001) //if the point is within .001 of the line then it is considered On the line
                    OnLine = true;
                else
                    OnLine = false;

            }
            return OnLine;
        }
    }
}