If we have 2 rectangles and we want to find out if they intersect, then we can do with following code:
CGRect b=CGRectMake(40, 50, 280, 200);
CGRect c=CGRectMake(100, 125, 80, 275);
BOOL contains=CGRectIntersectsRect(b, c);
if(contains) NSLog(@"yes"); else NSLog(@"no");
//This will print yes because b overlaps rect c and viceversa
If this is not what you were looking for CGRect, try this comprehensive LIST.