/in/foo.cc: In function 'int main()':
/in/foo.cc:23:34: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
    else if (i != j && (((1<<i)&x == 0) && ((1<<j)&x == 0)))
                                ~~^~~~
/in/foo.cc:23:53: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
    else if (i != j && (((1<<i)&x == 0) && ((1<<j)&x == 0)))
                                                   ~~^~~~