static void a(int x)
{
var alpha = "abcdefghjijklmnopqrstuvwxyz";
Console.WriteLine(alpha[x]);
}
static void b(int x)
{
Console.WriteLine((char)(x+'a'));
}
static void c(int x)
{
var alpha = Enumerable.Range('a',26).Select(c=>(char)c);
Console.WriteLine(alpha.ElementAt(x));
}
static void d(int x)
{
var table = new Tuple<int,char>[]
{
new Tuple<int,char>(0,'a'),
new Tuple<int,char>(1,'b'),
new Tuple<int,char>(2,'c'),
new Tuple<int,char>(3,'d'),
// 以下'z'まで続く
};
Console.WriteLine(table.First(c=>c.Item1 == x).Item2);
}