Question

Suppose I have 4 integers.

int a = 4;
int b = 2;
int c = 4;
int d = 1;

How can I sort these integers from smallest to biggest. The output needs to be something like this: d, b, a, c Most methods of sorting only give me the value of the sorted integer. I need to know the name.

Edit: Well, I’m writing an AI algorithm. I have 4 ints that store direction priority. (If the AI comes into a wall, it chooses the next best direction). So, I need to find the lowest int, and if the AI can’t move that way, I choose the second to lowest etc.

Answer 1

Here is an objective-c approach. Unfortunately, you will not have the fun of writing the AI portion, the sorting is built into the libraries already.

int north = 1, south = 3, east = 2, west =4;

  NSDictionary * nDict = [NSDictionary dictionaryWithObjectsAndKeys:@"north", @"name", [NSNumber numberWithInt:north], @"value", nil];
  NSDictionary * sDict = [NSDictionary dictionaryWithObjectsAndKeys:@"south", @"name", [NSNumber numberWithInt:south], @"value", nil];
  NSDictionary * eDict = [NSDictionary dictionaryWithObjectsAndKeys:@"east", @"name", [NSNumber numberWithInt:east], @"value", nil];
  NSDictionary * wDict = [NSDictionary dictionaryWithObjectsAndKeys:@"west", @"name", [NSNumber numberWithInt:west], @"value", nil];


  NSArray * toBeSorted = [NSArray arrayWithObjects:nDict,sDict,eDict,wDict,nil];
  NSArray * sortDescriptors = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"value" ascending:NO]];
  NSArray * sorted = [toBeSorted sortedArrayUsingDescriptors:sortDescriptors];
  NSLog(@"sorted %@", sorted);

Output

2012-01-23 19:50:21.079 TestEnvironment[19792:207] sorted (
        {
        name = west;
        value = 4;
    },
        {
        name = south;
        value = 3;
    },
        {
        name = east;
        value = 2;
    },
        {
        name = north;
        value = 1;
    }
)

Now you can check the highest priority by

NSString * highestPriority = [[sorted objectAtIndex:0] objectForKey:@"name"];

Now you have some classes you can look up (NSArray, NSDictionary, NSSortDescriptor, NSNumber)