Do C# strings end with empty string?

Question

Just a short question out of curiosity.

string str = "string";
Console.WriteLine(str.EndsWith(string.Empty));                  //true
Console.WriteLine(str.LastIndexOf(string.Empty) == str.Length); //false
//of course string are indexed from 0, 
//just wrote if for fun to check whether empty string get some extra index
///somehow by a miracle:)

//finally

Console.WriteLine(str.LastIndexOf(string.Empty) 
               == str.LastIndexOf('g'));                        //true :)

Answer 1

EndsWith:

Determines whether the end of this string instance matches the specified string.

All strings will match "" at the end... or any other part of the string. Why? Because conceptually, there are empty strings around every character.

"" + "abc" + "" == "abc" == "" + "a" + "" + "b" + "" + "c" + ""

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Update:

About your last example - this is documented on LastIndexOf:

If value is String.Empty, the return value is the last index position in this instance.

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A related issue is the use of null as a string terminator - which happens in C and C++, but not C#.

From MSDN - String Class (System):

In the .NET Framework, a String object can include embedded null characters, which count as a part of the string's length. However, in some languages such as C and C++, a null character indicates the end of a string; it is not considered a part of the string and is not counted as part of the string's length.

Answer 2

Try this:

string str = "string";
Console.WriteLine(str.EndsWith(string.Empty));                  //true 
Console.WriteLine(str.LastIndexOf(string.Empty) == str.Length-1); // true
Console.ReadLine();

So yes as Oded said, they do always match.