/in/foo.cc:1:1: error: expected unqualified-id before 'for'
    1 | for (int j=i;j<=n;j++)
      | ^~~
/in/foo.cc:1:14: error: 'j' does not name a type
    1 | for (int j=i;j<=n;j++)
      |              ^
/in/foo.cc:1:19: error: 'j' does not name a type
    1 | for (int j=i;j<=n;j++)
      |                   ^
/in/foo.cc:8:9: error: expected unqualified-id before 'if'
    8 |         if (ok==0)
      |         ^~