int A_VALUE = 1 << 0; // 0001 -> 0001   =  1
int B_VALUE = 1 << 1; // 0001 -> 0010   =  2
int C_VALUE = 1 << 2; // 0001 -> 0100   =  4
int D_VALUE = 1 << 3; // 0001 -> 1000   =  8
int E_VALUE = 1 << 4; // 0001 -> 10000  =  16
int F_VALUE = 1 << 5; // 0001 -> 100000 =  32

Console.WriteLine(A_VALUE); //1
Console.WriteLine(B_VALUE); //2
Console.WriteLine(C_VALUE); //4
Console.WriteLine(D_VALUE); //8
Console.WriteLine(E_VALUE); //16
Console.WriteLine(F_VALUE); //32

//& 與運算子也就是二進位制與運算
int x = 0 , y = 1;
Console.WriteLine( x & y ); // 0
Console.WriteLine( x & x ); // 0
Console.WriteLine( y & y ); // 1