Randomizing Square colors [closed] - ios

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I have four squares on my screen and I want each of the squares to display a different image every time for each square. I have got it to work, but as the code repeats sometimes there is a delay. I'm not sure what I'm doing wrong.
Here is my main code
#import "HomeScreenViewController.h"
#interface HomeScreenViewController ()
#end
#implementation HomeScreenViewController
-(void)startRandomSquares
{
self.greenImage = [UIImage imageNamed:#"GreenSquare.png"];
self.redImage = [UIImage imageNamed:#"RedSquare"];
self.blueImage = [UIImage imageNamed:#"BlueSquare"];
self.purpleImage = [UIImage imageNamed:#"PurpleSquare"];
self.arrayOfColors = [NSMutableArray arrayWithObjects:self.greenImage,self.redImage, self.blueImage, self.purpleImage, nil];
}
-(IBAction)Button1:(id)sender
{
self.startLabel.hidden = YES;
}
-(IBAction)Button2:(id)sender
{
}
-(IBAction)Button3:(id)sender
{
}
-(IBAction)Button4:(id)sender
{
}
-(void)randomizeAllSquares
{
[self randomizedSquare1];
[self randomizedSquare2];
[self randomizedSquare3];
[self randomizedSquare4];
}
-(void)randomizedSquare1
{
[self startRandomSquares];
randomColor = arc4random() % [self.arrayOfColors count];
square1RandomNumber = randomColor;
// NSLog(#"Square 1 : %d", square1RandomNumber);
//NSLog(#"Square 1 colors : %#", self.arrayOfColors);
switch (square1RandomNumber) {
case 0:
self.square1.image = self.arrayOfColors[0];
break;
case 1:
self.square1.image = self.arrayOfColors[1];
break;
case 2:
self.square1.image = self.arrayOfColors[2];
break;
case 3:
self.square1.image = self.arrayOfColors[3];
break;
default:
break;
}
if (square1RandomNumber == square2RandomNumber ) {
[self randomizedSquare1];
NSLog(#"Square 1-2 MATCH!!!");
}
if (square1RandomNumber == square4RandomNumber) {
[self randomizedSquare1];
NSLog(#"Square 1-4 Match!!!");
}
}
-(void)randomizedSquare2
{
[self startRandomSquares];
randomColor = arc4random() % [self.arrayOfColors count];
square2RandomNumber = randomColor;
//NSLog(#"Square 2 : %d", square2RandomNumber);
//NSLog(#"Square 2 colors : %#", self.arrayOfColors);
switch (square2RandomNumber) {
case 0:
self.square2.image = self.arrayOfColors[0];
break;
case 1:
self.square2.image = self.arrayOfColors[1];
break;
case 2:
self.square2.image = self.arrayOfColors[2];
break;
case 3:
self.square2.image = self.arrayOfColors[3];
break;
default:
break;
}
if (square2RandomNumber == square1RandomNumber ) {
[self randomizedSquare2];
NSLog(#"Square 2-1 Match!!!");
}
if (square2RandomNumber == square4RandomNumber) {
[self randomizedSquare2];
NSLog(#"Square 2-4 Match!!!");
}
}
-(void)randomizedSquare3
{
[self startRandomSquares];
randomColor = arc4random() % [self.arrayOfColors count];
square3RandomNumber = randomColor;
//NSLog(#"Square 3 : %d", square3RandomNumber);
//NSLog(#"Square 3 colors : %#", self.arrayOfColors);
switch (square3RandomNumber) {
case 0:
self.square3.image = self.arrayOfColors[0];
break;
case 1:
self.square3.image = self.arrayOfColors[1];
break;
case 2:
self.square3.image = self.arrayOfColors[2];
break;
case 3:
self.square3.image = self.arrayOfColors[3];
break;
default:
break;
}
if (square3RandomNumber == square2RandomNumber ){
[self randomizedSquare3];
NSLog(#"Square 3 - 2 MATCH!!!");
}
if (square3RandomNumber == square1RandomNumber) {
[self randomizedSquare3];
NSLog(#"Square 3- 1 MATCH!!");
}
}
-(void)randomizedSquare4
{
[self startRandomSquares];
randomColor = arc4random() % [self.arrayOfColors count];
square4RandomNumber = randomColor;
//NSLog(#"Square 4 : %d", square4RandomNumber);
//NSLog(#"Square 4 colors : %#", self.arrayOfColors);
switch (square4RandomNumber) {
case 0:
self.square4.image = self.arrayOfColors[0];
break;
case 1:
self.square4.image = self.arrayOfColors[1];
break;
case 2:
self.square4.image = self.arrayOfColors[2];
break;
case 3:
self.square4.image = self.arrayOfColors[3];
break;
default:
break;
}
if (square4RandomNumber == square2RandomNumber ) {
[self randomizedSquare4];
NSLog(#"Square 4-2 MATCH!!");
}
if (square4RandomNumber == square1RandomNumber) {
[self randomizedSquare4];
NSLog(#"SQuare 4-1 MATCH!!");
}
if (square4RandomNumber == square3RandomNumber) {
[self randomizedSquare4];
NSLog(#"Square 4-3 Match");
}
}

Answer 1

Ouch, that's a lot of code duplication. In general if you find yourself writing a similar piece of code multiple times it's not just best practice to generalize it, but you'll likely end up with a better solution.
A simple shuffle function on your array along with a simple reassign would work, and will give a runtime of N (ie the loop will only go through the array once per call). What you have now will technically try to create the color for a square multiple times in the case that it finds a match which is the reason for your slowness. Square 4 has a 3/4 chance that it will get the same color as another square so it likely runs at least 3 times before stopping.
- (void)shuffleImages
{
//uses the Fisher-Yates shuffle algorithm
for (NSUInteger i = self.arrayOfColors.count - 1; i >= 1; i--)
{
int index = arc4random_uniform(i+1);
[self.arrayOfColors exchangeObjectAtIndex:index withObjectAtIndex:i];
}
}
- (void)updateImages
{
[self shuffleImages];
self.square1.image = self.arrayOfColors[0];
self.square2.image = self.arrayOfColors[1];
self.square3.image = self.arrayOfColors[2];
self.square4.image = self.arrayOfColors[3];
}
All you need to do when you want your colors to change is call the updateImages function.

Answer 2

The delay comes from the check at the end of each randomisation. There's a 75% chance the number generated is in one of the other 3 squares, so it will loop and loop until it generates the only number it can be.
A better solution would be to shuffle the array of images, and then assign each image to each view in order.
e.g. (pseudo-code)
shuffle array of images
view 1 = array[0]
view 2 = array[1]
...
view 4 = array[3]

Answer 3

Brandon is right about the insane amount of code duplication, and using the fischer-yates algorithm is definitely the right way to go, but it sounds like you also want this to repeat, so you should use an NSTimer.
#property (strong, nonatomic) NSTimer *randomizeColorTimer;
- (void)startRandomizing
{
_randomizeColorTimer = [NSTimer scheduledTimerWithTimeInterval:0.25
target:self
selector:#selector(shuffleImages)
userInfo:nil
repeats:YES];
}
- (void)stopRandomizing
{
[_randomizeColorTimer invalidate];
_randomizeColorTimer = nil;
}