/in/foo.c: In function 'main':
/in/foo.c:15:9: error: expected expression before 'int'
   15 |     add(int i,int n);
      |         ^~~
/in/foo.c:15:5: error: too few arguments to function 'add'
   15 |     add(int i,int n);
      |     ^~~
/in/foo.c:2:5: note: declared here
    2 | int add(int i,int n)
      |     ^~~