/in/foo.cc: In function 'int main()':
/in/foo.cc:8:13: error: 'log' was not declared in this scope
   if(log(i-1)<n&&log(i)>=n)
             ^
/in/foo.cc:5:12: warning: unused variable 'j' [-Wunused-variable]
  int n,x,i,j;
            ^