std::iota

template <class ForwardIterator, class T>  void iota (ForwardIterator first, ForwardIterator last, T val);

Store increasing sequence

Assigns to every element in the range [first,last) successive values of val, as if incremented with ++val after each element is written.

The behavior of this function template is equivalent to:

template <class ForwardIterator, class T>
  void iota (ForwardIterator first, ForwardIterator last, T val)
{
  while (first!=last) {
    *first = val;
    ++first;
    ++val;
  }
}

Parameters

first, last: Forward iterators to the initial and final positions of the sequence to be written. The range used is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
val: Initial value for the accumulator.

Return value

none

Example

// iota example
#include <iostream>     // std::cout
#include <numeric>      // std::iota

int main () {
  int numbers[10];

  std::iota (numbers,numbers+10,100);

  std::cout << "numbers:";
  for (int& i:numbers) std::cout << ' ' << i;
  std::cout << '\n';

  return 0;
}

Output:


numbers: 100 101 102 103 104 105 106 107 108 109

Complexity

Linear in the distance between first and last (increments and assignments).

Data races

The elements in the range [first,last) are modified (each element is modified exactly once).

Exceptions

Throws if any of the assignments or increments throws.
Note that invalid arguments cause undefined behavior.