프로그램이 루프에 멈춤

Here is a modified version of your code, as mentioned in the comments i used vectors instaed of arrays, because you can use vector without knowing the size of it, which is the opposite of declaring arrays, at compile time the compiler must know the size of the array, but you define an array and you give it a size which is not a constant at compile time, i commented the part of the code where you use the array index[] because i dont know why you are printing what the array has, while it is empty, you dont have anything inside it you just declared it.

here is the code hope it fulfill your needs.

#include<string>
#include<vector>
#include<iostream>



using namespace std;


int main(){


    int n_in = 0;
  int keys = 0;
  cin>>n_in;
  vector<long long> in_array;

  for(int i=0; i<n_in; i++){
      int k =0;
      cin >> k;

    in_array.push_back(k);
  }
  cout<<"Executed"; 
  cin>>keys;
  cout<<"Executed"<<" "<<keys;

  vector<int> index;
  vector<long long> key_array;
  cout<<"Executed";

  for(int j=0; j<keys; j++){
      int p =0;

    cin>>p ;
        key_array.push_back(p);
    cout<<"Iteration" <<j<<"complete" ;
  }
  cout<<"Executed";
  //bin_search(in_array, n_in, key_array, keys, index);

  /*for(int i=0; i<keys; i++){
      int m =0;

    cout<<index[i]<<" " ;
  }
*/

    return 0;
}

Edit: What you said in the comment is true in C, but in c++ the compiler need to have the exact size of the array when compiling, otherwise you will have to use the new operator to dynamically allocate memory.

예를 들면 :

int MyArray[5]; // correct

또는

const int ARRAY_SIZE = 6;
int MyArray[ARRAY_SIZE]; // correct

그러나

int ArraySize = 5;
int MyArray[ArraySize]; // incorrect

그것을 요 ​​약하기:

배열의 요소 수는 상수 표현식이어야합니다. 변수 경계가 필요한 경우 벡터를 사용하십시오.