c# overriding operator in MyString class returns the same object

Question

I want to override -- operator for MyString class. It should find the shortest word in string. Here is code:

class MyString
{
    private string data;
    public string Data
    {
        get { return data; }
        set { data = value; }
    }

    public MyString(string s)
    {
        Data = s;
    }

    public MyString(MyString s)
    {
        Data = s.Data;
    }

    public static MyString operator --(MyString s)
    {
        var words = s.Data.Split();
        int l = 99999, ind = 0;
        for (int i = 0; i < words.Length; i++)
        {
            if (words[i].Length < l)
            {
                ind = i;
                l = words[i].Length;
            }
        }
        MyString result = new MyString(words[ind]);
        return result;
    }
}

When I try to use it like this:

    MyString s1, shortest;
    s1 = new MyString("one two three");
    shortest = s1--;
    Console.WriteLine(shortest.Data);

it returns "one two three" instead of "one". How can I fix it?

For the love of god don't do this. Why would anyone know to use that operator which has nothing to do with what you want it to do? Also, if your goal is to _"find the shortest word in string"_ write a method called `FindTheShortestWord()` and use that — maccettura, Feb 14 '18 at 15:42
@st_dec if a school gave you that task, get your money back. — maccettura, Feb 14 '18 at 16:04

score 3 · Accepted Answer · answered Feb 14 '18 at 15:37

var x = foo--;

is post-decrement, i.e. similar to:

var x = foo;
foo--;

You might want pre-decrement, i.e.

var x = --foo;

which is similar to:

foo--;
var x = foo;

Either way: it inappropriately changes foo, which you probably don't want. If you do:

shortest = --s1;
Console.WriteLine(shortest.Data);
Console.WriteLine(s1.Data);

You'll see that s1.Data is also now "one".

I suggest instead:

shortest = s1.GetShortestWord();
Console.WriteLine(shortest.Data);

c# overriding operator in MyString class returns the same object

1 Answers1