std::unique_ptr<T,Deleter>::operator[] (3) - Linux Manuals

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

NAME

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

Synopsis

T& operator[](size_t i) const; (since C++11)

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.

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