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A type that provides read-only access to elements in a vector.

typedef typename Allocator::const_reference const_reference;

A type const_reference cannot be used to modify the value of an element. You can use const_reference on non-const elements but you must use const_reference on const elements.

// vector_const_ref.cpp
// compile with: /EHsc
#include <vector>
#include <iostream>

int main( )
   using namespace std;
   vector <int> v1;
   v1.push_back( 10 );
   v1.push_back( 20 );

   const vector <int> v2 = v1;
   const int &i = v2.front( );
   const int &j = v2.back( );
   cout << "The first element is " << i << endl;
   cout << "The second element is " << j << endl;
   // The following line would cause an error as v2 is const
   // v2.push_back( 30 );
The first element is 10
The second element is 20

Header: <vector>

Namespace: std

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