operator << in c# [duplicate]

Question

i couldn't understand this code in c#

int i=4 
int[] s =new int [1<<i]; 
Console.WriteLine(s.length); 

the ouput is 16 i don't know why the output like that?

Answer 1

bit shift operator

Answer 2

From documentation

If first operand is an int or uint (32-bit quantity), the shift count is given by the low-order five bits of second operand.

If first operand is a long or ulong (64-bit quantity), the shift count is given by the low-order six bits of second operand.

Note that i<<1 and i<<33 give the same result, because 1 and 33 have the same low-order five bits.

This will be the same as 2^( the actual value of the lower 5 bits ).

So in your case it would be 2^4=16.