Push and Pop Method

class Program
    {
        struct Stack<G>
        {

            public G[] arr;
            public int top;
            public void Push(G val)
            {
                if (top < arr.Length - 1)
                {
                    top++;
                    arr[top] = val;
                }
            }
            public void Pop()
            {
                if (top == -1)
                {
                    Console.WriteLine("Stack is empty");
                }
                else
                {
                    Console.WriteLine(arr[top]);
                    top--;
                }
            }
        }
        static void Main(string[] args)
        {
            Stack<int> s;
            s.top = -1;
            s.arr = new int[5];
            s.Push(1);
            s.Push(5);
            s.Push(7);
            s.Pop();
        }
    }