/in/foo.c: In function 'main':
/in/foo.c:5:9: error: 'cin' undeclared (first use in this function)
    5 |         cin>>n>>k;
      |         ^~~
/in/foo.c:5:9: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:7:22: error: 'numbers' undeclared (first use in this function)
    7 |         scanf("%d", &numbers[i]);
      |                      ^~~~~~~