How do I say this?

Let's try...

I'm doing a program that finds a path between two given points. All points have an integer value, and they reside in an array, like this:

100 - 101
100 - 105
100 - 108
101 - 102
101 - 108
102 - 224
103 - 224
...
108 - 120
...
120 - 224


This means that from 100, the path goes either to 101, 105, or 108.

If the given start and end points were 100 - 224, the answer path would be 100-101-102-224 OR 100-108-120-224.

But how do I make this program?
Where do I start?

Thanks in advanks...

D