/in/foo.c: In function 'main':
/in/foo.c:10:17: error: lvalue required as left operand of assignment
   10 |         {if (a%i=0)
      |                 ^
/in/foo.c:16:16: error: 'o' undeclared (first use in this function)
   16 |         return o;
      |                ^
/in/foo.c:16:16: note: each undeclared identifier is reported only once for each function it appears in