generic stack implementation, C#

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//Generic Stack
//Rextester.Program.Main is the entry point for your code. Don't change it.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
          MyStack<int> myStack = new MyStack<int>(5); // default constructor will initialize the stack for 100 capacity. Another constructor to take an array will be nice.
            
          myStack.push(1);
          Assert(1 == myStack.pop(), "First item pop");
          
          try
          {
            myStack.pop();
            Assert(false, "Exception was not thrown when stack is empty.");
          }
          catch (Exception) //use an existing exception like StackIsEmpty if available or create a custom one
          {
              Assert(true, "Exception was thrown correctly when stack is empty.");
          }
            
          myStack.push(1);
          myStack.push(2);
          myStack.push(3);
          Assert(3 == myStack.pop(), "last in first out");
          myStack.push(3);
          myStack.push(4);
          myStack.push(5);
            
          try
          {
            myStack.push(6);
            Assert(false, "Exception was not thrown when stack is full.");
          }
          catch (StackOverflowException) 
          {
              Assert(true, "Exception was thrown correctly when stack is full.");
          }
            
        }
        
        public static void Assert(bool result, string message)
        {
            Console.WriteLine("ASSERT: {0} - {1}", result.ToString(), message);
        }
        
        public class MyStack<T>
        {
           T[] _items = null;
           int _currentIndex = 0;
            
           public MyStack() : this(100){}
            
            public MyStack(int capacity) {
                _items = new T[capacity];
            }
            
            public void push(T item)
            {
                if (_currentIndex >= _items.Length) { throw new StackOverflowException();}
                
                _items[_currentIndex] = item;
                
                _currentIndex++;
            }
            
            public T pop() 
            {
                
                if (_currentIndex <= 0) { throw new Exception(); }
                
                _currentIndex--;
                
                Console.WriteLine("current index: {0}", _currentIndex);
                
                return _items[_currentIndex];
            }
            
        }
        
    }
}

Show compiler warnings [ + ] Show input
Compilation time: 0.12 sec, absolute running time: 0.11 sec, cpu time: 0.08 sec, average memory usage: 17 Mb, average nr of threads: 4