array.m

#import <Foundation/Foundation.h>

int main() {
    NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];

    NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:
                                       [NSNumber numberWithInt:63], @"Mathematics",
                                       [NSNumber numberWithInt:72], @"English",
                                       [NSNumber numberWithInt:55], @"History",
                                       [NSNumber numberWithInt:49], @"Geography",
                                       nil];
    NSLog(@"%@", dict);
    NSArray *sortedKeysArray = [dict keysSortedByValueUsingSelector:@selector(compare:)];
    NSLog(@"%@", sortedKeysArray);

    [pool release];
    return 0;
}