Ios image collision with one imageview - ios

Question

I am making an app that has 2 UIImageViews but in each image view the image changes 3 times. How can I make it so that if image A collides with image B or C action happens but not with image A and so on. Here is the code for the image changing
ImageView Changing 1
This is a random change
Trap.center = CGPointMake(350,220);
Trap1 = rand() %3;
switch (Trap1) {
case 0:
Trap.image = [UIImage imageNamed:#"Image1.png"];
break;
case 1:
Trap.image = [UIImage imageNamed:#"Image2.png"];
break;
case 2:
Trap.image = [UIImage imageNamed:#"Image3.png"];
break;
default:
break;
}
ImageView Changing 2
This is set with a swipe and is copied for the other 2 changes.
-(IBAction)Change3:(id)sender{
UIImage *img = [UIImage imageNamed:#"Image4.tif"];
[Change3 setImage:img];
}

Answer 1

You can add a tag to your Trap object. Compare the tags and if they are different, do something.
Set tag:
switch (Trap1) {
case 0:
Trap.image = [UIImage imageNamed:#"Image1.png"];
Trap.tag = 1;
break;
case 1:
Trap.image = [UIImage imageNamed:#"Image2.png"];
Trap.tag = 2;
break;
case 2:
Trap.image = [UIImage imageNamed:#"Image3.png"];
Trap.tag = 3;
break;
default:
break;
}
Compare tags
If (trap1.tag != trap2.tag){
//Do something
}