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 std::out_of_range exception.
Remarks
If the return value of at is assigned to a const_reference, the element it points to 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>
using namespace std;
int main( )
{
vector <int> vec;
vec.push_back(10);
vec.push_back(20);
const int &i = vec.at(0);
int &j = vec.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