Question

Hi I am new to iPhone. What I am doing is sorting the array of images; that array consists of 22 elements. I am writing the code for that:

NSMutableArray *images2 = [[NSMutableArray alloc] initWithArray:images]
int n=22;
for (int i=0;i<n;i++){

    for (int j=1;j<n-i;j++){
        if(count[j-1]>count[j]){
            int t = count[j-1]
            count[j-1] = count[j]
            count[j] =t ;

            NSString *tempimage = [images objectAtIndex:j-1];
            [images2 replaceobjectAtIndex:j-1 withobject:[image2 objectAtIndex:j]];
            [images2 replaceobjectAtIndex:j withobject:tempimage];
        }
    }
}
images = [[NSMutableArray alloc] initWithArray:images2];

It sorts finely but at the end it replaces 21st image. What is the wrong in this? If there are any mistakes please post the correct code. What I need is to replace first image to last and second image to first.

Answer 1

Solution to your problem: don’t implement sorting yourself, let the framework do it for you. NSMutableArray has a number of sorting methods that will do all this stuff for you. If you can clarify a few points (see the comments on your question) we can help you construct the proper sorting method call.

– exchangeObjectAtIndex:withObjectAtIndex:
– sortUsingDescriptors:
– sortUsingComparator:
– sortWithOptions:usingComparator:
– sortUsingFunction:context:
– sortUsingSelector: