View Compilation Error

0_0_38824921_8120.cpp: In function 'int main()':
0_0_38824921_8120.cpp:74:17: error: no matching function for call to 'Fenwick<int>::init()'
   74 |         fen.init();
      |         ~~~~~~~~^~
0_0_38824921_8120.cpp:16:10: note: candidate: 'void Fenwick<T>::init(int) [with T = int]'
   16 |     void init(int n) {
      |          ^~~~
0_0_38824921_8120.cpp:16:10: note:   candidate expects 1 argument, 0 provided