Thread: unordered_map and const ??

Hi, me again (last one today I promise ) So the situation is : I am trying to create a class that holds some info and allow others to query the data structures inside my class but not to change it. I figured, the best way to achieve this would be just to set a pointer to the variable and be done with it, but it does not work like that . example :

Code:

#include <iostream>
#include <vector>
#include <unordered_map>

using namespace std;

class X{

  unordered_map<int,vector<int>> x;
  
  public:
    
   const unordered_map<int,vector<int>> *c; 
   X(int);
   void print();
};


X::X(int y){
x.clear();
for(int i = 0;i< 3;i++){
	x[0].push_back(y+i);
}
  c=&x;
}

void X::print(){
	for(int i = 0;i< 3;i++)
  cout << x[0][i] << "\n";
}


int main (){
	
	X a(6);
	a.print();
	cout << (*a.c)[0][1] << "\n";
	
	
	
}

if i remove remove const it works , but then x can be modified and i do not wish that. Now if i repeat all jist with vectors like this :

Code:

#include <iostream>
#include <vector>
#include <unordered_map>

using namespace std;

class X{

  vector<int> x;
  
  public:
    
   const vector<int> *c; 
   X(int);
   void print();
};


X::X(int y){
x.clear();
for(int i = 0;i< 3;i++){
	x.push_back(y+i);
}
  c=&x;
}

void X::print(){
	for(int i = 0;i< 3;i++)
  cout << x[i] << "\n";
}


int main (){
	
	X a(6);
	a.print();
	cout << (*a.c)[1] << "\n";
	
}

i get exactly what i want . Why can't I do the same with the above map/hash table?

Is there a better way to do this?

thnx