Reverse A string

NSString *s=text.text;

    int i=[s length];

    NSMutableString *arr=[[NSMutableString alloc]initWithCapacity:i];

    for ( int j=i-1; j>=0; j--) {

        [arr appendString:[NSString stringWithFormat:@"%c",[s characterAtIndex:j]]];

    }

    NSLog(@"%@",arr);