/in/foo.c: In function 'main':
/in/foo.c:8:7: error: expected expression before 'int'
    8 |   if (int i=1;i<=n;i++){
      |       ^~~
/in/foo.c:9:14: error: 'i' undeclared (first use in this function)
    9 |   factorial*=i;
      |              ^
/in/foo.c:9:14: note: each undeclared identifier is reported only once for each function it appears in