Why does this string initialization in an if statement prevent me from printing?

Question

i have little problem with if

{
    string nom;
    string ou;
    nom = "1";
    if (nom == "1")
    {
        nom +=1;
        ou = nom;
    }
    Console.Write(ou);
}

but i cant print ou value i dont know why

Answer 1

Another option is to set ou in an else:

if (nom == "1")
{
    nom +=1;
    ou = nom;
} else 
{
    ou = "blank value";
}