Strange behaviour of switch case with boolean value

Question

My question is not about how to solve this error(I already solved it) but why is this error with boolean value.

My function is

private string NumberT         


        

Answer 1

Well, there's been good explanation for causes of this issue, but there is one more solution to the problem, which was not mentioned. Just put default instead of second case:

    private string NumberToString(int number, bool flag)
    {
        string str;

        switch (flag)
        {
            case true:
                str = number.ToString("00");
                break;
            default:
                str = number.ToString("0000");
                break;
        }

        return str;
    }

It leaves compiler with no further thoughts about flag variable value as we always assign a default value in our switch statement.

Also consider if-else statement equivalent solution:

    private string NumberToString(int number, bool flag)
    {
        string str;

        if (flag)
            str = number.ToString("00");
        else
            str = number.ToString("0000");

        return str;
    }

I am not particularly fond of 'one-liners' (one line solutions), as they lack extendability and moreover - readability, but as the last resort just use ternary operators like this:

    private string NumberToString(int number, bool flag)
    {
        return flag ? number.ToString("00") : number.ToString("0000");
    }

While I am at it - consider using extension method + defaulting boolean to false, for example:

public static class intExtensions
{
    public static string NumberToString(this int number, bool flag = false)
    {
        return flag ? number.ToString("00") : number.ToString("0000");
    }
}

and then in main class:

        int intVal = 56;
        string strVal1 = intVal.NumberToString(true);
        string strVal2 = intVal.NumberToString();