Thread: Need Help! Random in MFC

Originally Posted by stephencalderon

Greetings!
I'm a beginner, still in school. I'm doing a small project in MFC. It's a basic animation of a ball bouncing off the four wall in a square. I don't exactly understand what this does randomly : srand((unsigned)time (NULL)). Also how would I use this to make the ball bounce randomly on the walls? Sorry if this is simple. Right now it bounce SE to SW to NW to NE. Once it hits the corners the ball then bounces across from corner to corner stuck that way.
Thanks!

You could use rand() as a means to vary the angle of rebount, making sure the ball doesn't find some static angle and resolve itself to bouncing continuously off the same points of the square.

srand() is a seeder for the random number generator. It creates a new sequence of pseudo random numbers for the rand() function to use. It's weakness is that if you use the same number every time (as previously explained) you will get the same sequence every time.

time() is the number of seconds since 00:00hrs Jan 1, 1970. Using it as a seed in srand pretty much guarantees you won't get the same sequence twice.