breakout: drand() just return positive number, so the ball only begins moving to right. Right?
or is there some way to make de ball go to left randomly?
You can multiply the output of drand by a number to get a random number between 0 and that number.
You can also set the range of the random number function to extend to be negative by subtracting from your negative number.
If you want a random number between -x and x, and y is the number drand48 output, you can do:
y * 2x - x
Hope that helps.