/in/foo.c: In function 'main':
/in/foo.c:10:17: error: 'flag' undeclared (first use in this function)
   10 |                 flag=i;
      |                 ^~~~
/in/foo.c:10:17: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:11:17: error: 'min' undeclared (first use in this function); did you mean 'main'?
   11 |                 min=a[i];
      |                 ^~~
      |                 main
/in/foo.c:12:21: error: 'j' undeclared (first use in this function)
   12 |                 for(j=i+1;j<n;j++){
      |                     ^