private static void Integral()
{
// for interoperability
sbyte sbi = 4;
short si = 5;
// First-class citizen
int i = 6; // default
long li = 7L;
var defi = 9; // int/Int32
System.Numerics.BigInteger bi = 11; // 16byte/128bit System.Int128?
Console.WriteLine("\nSigned integral underlying type:");
Console.WriteLine($"sbyte \t{sbi.GetType()} \t{Marshal.SizeOf(sbi)}");
Console.WriteLine($"short \t{si.GetType()} \t{Marshal.SizeOf(si)}");
Console.WriteLine($"int \t{i.GetType()} \t{Marshal.SizeOf(i)}");
Console.WriteLine($"long \t{li.GetType()} \t{Marshal.SizeOf(li)}");
Console.WriteLine($"default\t{defi.GetType()} \t{Marshal.SizeOf(defi)}");
Console.WriteLine($"BigInteger\t{bi.GetType()} \t{Marshal.SizeOf(bi)}");
}