Greetings from a newbie!

I'm creating a game of a sort where objects move and collide on a 2D ASCII map ( vector<vector if u will ). I'm having hard time calculating the projectories of ranged weaponry. Not sure if this problem is more mathematical than C++ related, but here goes.

When shooting a missile I create an object of the class Missile. It's member function moves it from source (x0,y0) to destination(x1,y1) moving one square at a time, in otherwords updating the objects private variables.

`int x_; int y_;`

Any tips how I should calculate the change in those variables in C++ ? A slope (maths!) would do the trick in algebra, but this puzzles me...

Thanks in advance.

-Topi