错误提示:不包含适合入口点的静态'main'方法?请高手帮我改一下这程序

Question

class Photo
    {
        string _title;
        public Photo(string title)//构造方式,并初始化照片名
        {
            this._title = title;
        }
        public string Title//照片名的属性
        {
            get
            {
                return _title;
            }
        }
    }    class Album
    {
        Photo[] photos;
        public Album(int capacity)//构造方式,并指定相册的大小
        {
            photos=new Photo[capacity];
        }
        public Photo this[int index]
        {
            get
            {
                if (index < 0 || index >= photos.Length)
                {
                    Console.WriteLine("索引无效");
                    return null;
                }
                return photos[index];
            }
            set
            {
                if (index < 0 || index >= photos.Length)
                {
                    Console.WriteLine("索引无效");
                    return;
                }
                photos[index] = value;
            }
        }
        public Photo this[string title]
        {
            get
            {
                foreach (Photo p in photos)//遍历数组中的所有照片
                {
                    if (p.Title == title)
                    {
                        return p;
                    }                    
                }
                Console.WriteLine("未找到");
                return null;
            }
        }
    }    class TestIndexr
    {
        static void main(string[] args)
        {
            Album friends = new Album(3);            Photo first = new Photo("Jenn");
            Photo second = new Photo("Smith");
            Photo third = new Photo("Mark");
            friends[0] = first;
            friends[1] = second;
            friends[2] = third;            Photo obj1Photo = friends[2];
            Console.WriteLine(obj1Photo.Title);            Photo obj2Photo = friends["Jenn"];
            Console.WriteLine(obj2Photo.Title);        }
    }

Answer 1

晕,原来一个是大写,谢谢提醒