Getting "Use of unassigned local variable" C# error

Question

namespace FirstApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(GetDay(0));
            Console.ReadLine();
        }
        static string GetDay(int daynum)
        {
            string dayname;
            switch (daynum)
            {
                case 0:
                    dayname = "sunday";
                    break;
            }
            return dayname;
        }

    }
}

Answer 1

static string GetDay(int dayNum) {
  string dayname = String.Empty;
  switch(dayNum) {
   case 0:
    dayname = "sunday";
    break;
  }
  return dayname;
}

Answer 2

Use this line instead:

        string dayname = "";

that way if none of you case statements match, the function can return an empty string;

Otherwise if DayNum != 0, the function has nothing to return - which is why you are getting the error.