/in/foo.c: In function 'main':
/in/foo.c:8:23: error: expected expression before ';' token
    8 |                 for(j=;j<=i;j++)
      |                       ^
/in/foo.c:14:39: error: 'num' undeclared (first use in this function); did you mean 'sum'?
   14 |                         printf("%d\n",num);
      |                                       ^~~
      |                                       sum
/in/foo.c:14:39: note: each undeclared identifier is reported only once for each function it appears in