随机数

gistfile1.m

// 产生随机数种子
srandom((unsigned)time(NULL));

- (CGPoint)randomPoint
{
    CGPoint result;
    NSRect r = [self bounds];
    result.x = r.origin.x + random()%(int)r.size.width;
    result.y = r.origin.y + random()%(int)r.size.height;
    return result;
}