std::vector::operator[]

 

C++

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reference       operator[]( size_type pos );
const_reference operator[]( size_type pos ) const;

Returns a reference to the element at specified location pos. No bounds checking is performed.

Parameters

pos

-

position of the element to return

Return value

reference to the requested element

Complexity

Constant

Example

The following code uses operator[] read from and write to a std::vector<int>:

#include <vector>
#include <iostream>
 
int main()
{
    std::vector<int> numbers {2, 4, 6, 8};
 
    std::cout << "Second element: " << numbers[1] << '\n';
 
    numbers[0] = 5;
 
    std::cout << "All numbers:";
    for (auto i : numbers) {
        std::cout << ' ' << i;
    }
    std::cout << '\n';
}

Output:

Second element: 4
All numbers: 5 4 6 8

See also

at	access specified element with bounds checking (public member function)