How can i add a symbol between the array of strings in this method? I tried using an if statement within the for each loop that added the symbol between each index of the array but it didn't work. 

```
    public string addSymbolBetweenStringArray(string[] strArray, string symbol)
    {
        string s = default(string);
        foreach (string str in strArray)
        {

        }
        return s;
    }

    string[] strArray = { "Hello", "World", };
    string symbol = "-";
    addSymbolBetweenStringArray(stringArray, symbol);

```

The method then returns Hello-World