Any one can explain this code?

Question

#include <iostream>
using namespace std;
int main() {
int a=3;
a^=9;
cout<<a<<endl;
return 0;
}

Answer 1

a ^= 9 is the same as a = a ^ 9

a = 3

so

a = 3 ^ 9

^ is the bitwise (i.e. binary) XOR operator.

When one, and only one, of the expressions has a 1 in a digit, the result has a 1 in that digit. Otherwise, the result has a 0 in that digit.

3 in binary is 0011
9 in binary is 1001
--------
3 ^ 9 is 1010

1010 binary is 10 in base 10

So the output is 10.

Answer 2

C++ XOR operator
http://www.cplusplus.com/doc/boolean/

Answer 3

thanks @david ashton