/in/foo.cc: In function 'int main()':
/in/foo.cc:33:5: error: 'strcpy' was not declared in this scope
   33 |     strcpy(tempnam, arr[n].nam);
      |     ^~~~~~
/in/foo.cc:3:1: note: 'strcpy' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    2 | #include<algorithm>
  +++ |+#include <cstring>
    3 | using namespace std;