std::merge

Parameters

first1, last1

Input iterators to the initial and final positions of the first sorted sequence. The range used is [first1,last1), which contains all the elements between first1 and last1, including the element pointed by first1 but not the element pointed by last1.

first2, last2

Input iterators to the initial and final positions of the second sorted sequence. The range used is [first2,last2).

result

Output iterator to the initial position of the range where the resulting combined range is stored. Its size is equal to the sum of both ranges above.

comp

Binary function that accepts two arguments of the types pointed by the iterators, and returns a value convertible to bool. The value returned indicates whether the first argument is considered to go before the second in the specific strict weak ordering it defines.
The function shall not modify any of its arguments.
This can either be a function pointer or a function object.

Return value

Example

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// merge algorithm example
#include <iostream>     // std::cout
#include <algorithm>    // std::merge, std::sort
#include <vector>       // std::vector
int main () {
  int first[] = {5,10,15,20,25};
  int second[] = {50,40,30,20,10};
  std::vector<int> v(10);
  std::sort (first,first+5);
  std::sort (second,second+5);
  std::merge (first,first+5,second,second+5,v.begin());
  std::cout << "The resulting vector contains:";
  for (std::vector<int>::iterator it=v.begin(); it!=v.end(); ++it)
    std::cout << ' ' << *it;
  std::cout << '\n';
  return 0;
}

The resulting vector contains: 5 10 10 15 20 20 25 30 40 50

Complexity

Data races

Exceptions

See also

inplace_merge

Merge consecutive sorted ranges (function template)

set_union

Union of two sorted ranges (function template)

copy

Copy range of elements (function template)