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using System;
using System.Collections.Generic;

public class Program
{
	public static void Main()
	{
		
		#region Assignment compatibility
			
		string str = "Test";
		
		//An object of a more derived type is assigned to an object of a less derived type.
		object obj1 = str;
		
		#endregion Assignment compatibility
			
			
			
		#region Covariance (Array)
		
		object[] array = new String[10];
		
		//But this operation is not type safe
		// The following statement produces a run-time exception.  
		// array[0] = 10; 
		
		#endregion Covariance (Array)
			
			
			
		#region Covariance (Generic Interface)
			
		IEnumerable<string> strings = new List<string>();
		
		// An object that is instantiated with a more derived type argument 
		// is assigned to an object instantiated with a less derived type argument.
		// So, assignment compatibility is preserved.
		IEnumerable<object> objects = strings;
		
		#endregion Covariance (Generic Interface)
			
			
			
			
		#region Covariance (In Delegates)
			
		// A delegate specifies a return type as object, 
		// but you can assign a method that returns as string.
		Func<object> del = GetString;
				
		#endregion Covariance (In Delegates)
			
			
			
			
		#region Contravariance (In Delegates)		
	
		// An object that is instantiated with a less derived type argument
		// is assigned to an object instantiated with a more derived type argument.
		// So, assignment compatibility is reversed.
		Action<string> del2 = SetObject;
		
		#endregion Contravariance (In Delegates)
		
	}

	
	static void SetObject(object o) { }
	
	static string GetString() { return ""; }
}

 
using System;
using System.Collections.Generic;
​
public class Program
{
    public static void Main()
    {
        
        #region Assignment compatibility
            
        string str = "Test";
        
        //An object of a more derived type is assigned to an object of a less derived type.
        object obj1 = str;
        
        #endregion Assignment compatibility
            
            
            
        #region Covariance (Array)
        
        object[] array = new String[10];
        
        //But this operation is not type safe