/in/foo.cc: In function 'int main()':
/in/foo.cc:42:14: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
      a|=(1<<x-1);
             ~^~
/in/foo.cc:57:14: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
      a|=(1<<x-1);
             ~^~
/in/foo.cc:63:22: warning: suggest parentheses around arithmetic in operand of '|' [-Wparentheses]
            int t1=(s1^(s1&a)|(s0&a));
                    ~~^~~~~~~