/in/foo.cc: In function 'int lcm(int, int)':
/in/foo.cc:14:20: error: 'grd' cannot be used as a function
   14 |         lcm=a*b/grd(a,b);
      |                 ~~~^~~~~
/in/foo.cc:15:16: error: invalid conversion from 'int (*)(int, int)' to 'int' [-fpermissive]
   15 |         return lcm;
      |                ^~~
      |                |
      |                int (*)(int, int)