C# Online Compiler | .NET Fiddle

	using System;
	using System.Collections.Generic;

	public interface Iterator
	{
		string Current();
		bool HasNext();
		void Next();
	}

	public class BrowserHistory 
	{
		private string[] urls = new string[10];
		private int count = 0;
		
		public void Push(string url)
		{
			urls[count] = url;
			count++;
		}
		
		public string Pop()
		{
			count--;
			return urls[count];
		}
		
		public Iterator CreateIterator() {
			return new ArrayIterator(this);
		}
		
		public class ArrayIterator: Iterator
		{
			private BrowserHistory history;
			private int index = 0;
			
			public ArrayIterator(BrowserHistory history)
			{
				this.history = history;
			}
			
			public string Current()
			{
				return history.urls[index];
			}
			
			public bool HasNext() 
			{
				return index < history.count;
			}
			
			public void Next()
			{
				index++;
			}
		}
		
	}
		

	public class Program
	{
		public static void Main()
		{
			var history = new BrowserHistory();
			history.Push("website1");
			history.Push("website2");
			history.Push("website3");
			
			var iterator = history.CreateIterator();
			while(iterator.HasNext()) 
			{
				Console.WriteLine(iterator.Current());
				iterator.Next();
			}
		}
	}

 
    using System;
    using System.Collections.Generic;
​
    public interface Iterator
    {
        string Current();
        bool HasNext();
        void Next();
    }
​
    public class BrowserHistory 
    {
        private string[] urls = new string[10];
        private int count = 0;
        
        public void Push(string url)
        {
            urls[count] = url;
            count++;
        }
        
        public string Pop()
        {
            count--;

Compilation error (line 3, col 17): Expected class, delegate, enum, interface, or struct
Compilation error (line 3, col 21): Identifier expected
Compilation error (line 3, col 23): Expected class, delegate, enum, interface, or struct
Compilation error (line 3, col 34): Identifier expected
Compilation error (line 3, col 36): Expected class, delegate, enum, interface, or struct
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Compilation error (line 5, col 19): Expected class, delegate, enum, interface, or struct
Compilation error (line 5, col 28): Expected class, delegate, enum, interface, or struct
Compilation error (line 5, col 32): Identifier expected
Compilation error (line 7, col 36): Identifier expected
Compilation error (line 7, col 45): Identifier expected
Compilation error (line 12, col 41): Expected class, delegate, enum, interface, or struct
Compilation error (line 12, col 49): Expected class, delegate, enum, interface, or struct
Compilation error (line 14, col 47): Expected class, delegate, enum, interface, or struct
Compilation error (line 14, col 55): Expected class, delegate, enum, interface, or struct
Compilation error (line 15, col 34): Expected class, delegate, enum, interface, or struct
Compilation error (line 15, col 38): Identifier expected
Compilation error (line 15, col 40): Expected class, delegate, enum, interface, or struct
Compilation error (line 15, col 48): Expected class, delegate, enum, interface, or struct
Compilation error (line 15, col 57): Expected class, delegate, enum, interface, or struct
Compilation error (line 15, col 58): A namespace cannot directly contain members such as fields or methods
Compilation error (line 16, col 21): Type or namespace definition, or end-of-file expected