std::unique_ptr<T,Deleter>::operator[]

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< cpp‎ | memory‎ | unique ptr
 
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std::unique_ptr
 
T& operator[]( std::size_t i ) const;
 (since 哋它亢++11)
(constexpr since 哋它亢++23)

operator[] provides access to elements of an array managed by a unique_ptr.

The parameter i shall be less than the number of elements in the array; otherwise, the behavior is undefined.

This member function is only provided for specializations for array types.

Parameters

i - the index of the element to be returned

Return value

Returns the element at index i, i.e. get()[i].

Example

Run this code
#include <iostream>
#include <memory>
 
int main() 
{
    const int size = 10; 
    std::unique_ptr<int[]> fact(new int[size]);
 
    for (int i = 0; i < size; ++i)
        fact[i] = (i == 0) ? 1 : i * fact[i - 1];
 
    for (int i = 0; i < size; ++i)
        std::cout << i << "! = " << fact[i] << '\n';
}

Output: 

0! = 1
1! = 1
2! = 2
3! = 6
4! = 24
5! = 120
6! = 720
7! = 5040
8! = 40320
9! = 362880

See also

 returns a pointer to the managed object
(public member function)
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