vector::at

Returns a reference to the element at a specified location in the vector.

reference at(
   size_type _Pos
);
const_reference at(
   size_type _Pos
) const;

Parameters

• _Pos
  The subscript or position number of the element to reference in the vector.

Return Value

A reference to the element subscripted in the argument. If _Off is greater than the size of the vector, at throws an exception.

Remarks

If the return value of at is assigned to a const_reference, the vector object cannot be modified. If the return value of at is assigned to a reference, the vector object can be modified.

Example

// vector_at.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 int &i = v1.at( 0 );
   int &j = v1.at( 1 );
   cout << "The first element is " << i << endl;
   cout << "The second element is " << j << endl;
}

The first element is 10
The second element is 20

Requirements

Header: <vector>

Namespace: std

See Also

Concepts

vector Class

vector Members

Standard Template Library