foo.cc: In function ‘int main()’:
foo.cc:11:9: error: ‘vector’ was not declared in this scope
   11 |         vector<char>c(n+1);
      |         ^~~~~~
foo.cc:5:1: note: ‘std::vector’ is defined in header ‘<vector>’; did you forget to ‘#include <vector>’?
    4 | #include<cmath>
  +++ |+#include <vector>
    5 | using namespace std;
foo.cc:11:16: error: expected primary-expression before ‘char’
   11 |         vector<char>c(n+1);
      |                ^~~~
foo.cc:17:22: error: ‘c’ was not declared in this scope
   17 |                 cin>>c[i];
      |                      ^