How to get data inside polygon or test if a point is inside or not

Hii friends

Help me out.. I have a program which asks the user to enter set of points.Based on this set of points the user should enter the x,y coordinates of the points which form a polygon. Now i have few points inside & outside the polygon..How to display the points or (x,y) coordinates of the point which is thier only inside the polygon comparing the polygon points. Please help me out

for triangle i can test if its inside & display the point but i am not getting for polygon..Please help me out..I am tryin past one week not getting...

For example:

the user

enters points as 7 & the x,y coordinates of it as

2,4

3,1

6,4

5,2

8,4

7,6

2,4

This points form a polygon

Now thier are some points which i should check if its inside the polygon or not & display it.

For the above example the points inside polygon are

3,3

6,3

& outside are

4,5

7,3

So when i check it wil display this value & tel inside if its inside or outside if its outside.. I want program like this..

please please help me out..

This a simple example.

I have huge data or set of points to check if its iside a region or not..

So it would be helpful i get this program so that i can try for my huge data.

Help me out