w3schools c# tutorial code example

Example: c# ?

/*
	A nullable value type T? represents all values of its underlying
    value type T and an additional null value. For example, you can 
    assign any of the following three values to a bool? variable: 
    true, false, or null.
*/

double? pi = 3.14;
char? letter = 'a';

int m2 = 10;
int? m = m2;

bool? flag = null;