How this is true?

Question

I got a question in a challenge in c++, it's confusing . question is, what is the output of this code:

Cout<<(1<<1)

Answer was 2

Answer 1

This link may help you

https://googleweblight.com/i?u=https://www.tutorialspoint.com/cplusplus/cpp_operators.htm&hl=en-NP

Answer 2

x<<y = x*(2^y)
1<<1 = 1*(2^1) = 2