集合对象（NSSet）

main.m

#import <Foundation/Foundation.h>
@interface NSSet(printInteger)
-(void)printSet;

@end
@implementation NSSet(printInteger)

-(void)printSet
{
    for (NSNumber *integer in self) {
        printf("%i",[integer integerValue]);
    }
    printf("\n");
}

@end

int main(void)
{
    @autoreleasepool {
        NSMutableSet *set1=[NSMutableSet setWithObjects:[NSNumber numberWithInteger:],
                            [NSNumber numberWithInteger:],
                            [NSNumber numberWithInteger:], nil];
        NSMutableSet *set2=[NSMutableSet setWithObjects:[NSNumber numberWithInteger:],
                            [NSNumber numberWithInteger:],
                            [NSNumber numberWithInteger:], nil];
        if ([set1 isEqualToSet:set2]==YES) {
            NSLog(@"set1=set2");
        }else{
            NSLog(@"set1!=set2");
        }
    if ([set1 containsObject:[NSNumber numberWithInteger:]]==YES) {
        NSLog(@"set1 included 3");
    }else{
        NSLog(@"set1 not included 3");
    }

    [set1 printSet];
    [set1 addObject:[NSNumber numberWithInteger:]];
    [set1 removeObject:[NSNumber numberWithInteger:]];
    [set1 printSet];
    [set1 intersectSet:set2];
    [set1 printSet];

    [set1 intersectSet:set2];
    [set1 printSet];
    [set1 unionSet:set2];
    [set1 printSet];
    }
    return ;
}