/in/foo.cc: In function 'int main()':
/in/foo.cc:15:26: error: 'b' cannot be used as a function
   15 |                         b(j+1)++;
      |                         ~^~~~~
/in/foo.cc:13:27: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   13 |                         if(x%j==0)
      |                           ^