Question

I have an object called Station in my system with these attributes:

@interface Station : NSObject {
NSString *stationID;
NSString *callsign;
NSString *stationState;
}

I also have an NSMutableArray containing 20 ‘Station’ objects as defined above.

I need to define a method which can can sort this array in 2 ways:
1) By stationID
2) By callsign

Can someone please explain how I can do this?

Answer 1

I’d use

NSInteger stationsSort( Station *station1, Station *station2, void *context) {
    if ( station1_greater_than_station2 )   {
        return NSOrderedDescending;
    }

    if ( station1_less_than_station2 ) {
        return NSOrderedAscending;
    }

    return NSOrderedSame;   
}

[myArray sortedArrayUsingFunction:stationsSort context:nil];