// 创建数组

    NSMutableArray *array = [NSMutableArray arrayWithObject:@"lier",@"hello",nil];

    [array addObject:[[Person alloc] init]];

   // 添加元素

    [array addObject:@"haha"];

    NSLog(@"%ld",array.count);

   NSMutableArray *array = [NSMutableArray arrayWithObject:@"lier",@"hello",nil];

    [array addObject:[[Person alloc] init]];

   // 添加元素

    [array addObject:@"haha"];

    NSLog(@"%ld",array.count);

    // 删除元素

    //[array removeAllObjects];

    // 删除指定的对象

    // [array removeObject:@"haha"];

    [array removeObjectAtIndex:];