How to code Bubble sorting For an Array of Objects in Objective C lang.?
+(void) SortAndPrintBubble:(NSMutableArray *) tosort{

    Student * tmp = [Student new];
    for (int i = [tosort count] - 1; i >=0; i--) {

        for (int j =1; j<=i; j++) {
            if ([[tosort objectAtIndex:(j-1)] GetGPA] > [[tosort objectAtIndex:j] GetGPA]) {
                tmp = [tosort objectAtIndex:(j-1)];
                [tosort insertObject:(id)[tosort objectAtIndex:(j-1)] atIndex:(NSUInteger)j];
                [tosort replaceObjectAtIndex:j withObject:(id)tmp];
            }
        }

-(NSComparisonResult) compareGPA:(Student*)otherStudent;

[tosort sortUsingSelector:@selector(compareGPA:)];

- (void)sortUsingFunction:(NSInteger (*)(id, id, void *))compare context:(void *)context