2.

2.#

 1#include <iostream>
 2
 3using namespace std;
 4
 5void print(char const* s, int& num) {
 6  if (*s == '\0') {
 7    return;
 8  }
 9  num++;
10  print(s + 1, num);
11  cout << *s;
12}
13
14int main() {
15  int n      = 0;
16  char str[] = "chatgpt";
17  print(str, n);
18  cout << endl << n;
19}