# algorithm - Replacing a range between two iterators in C++

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### algorithm - Replacing a range between two iterators in C++

Assume I have two non-constant iterators begin and end. I want to completely replace the range between begin and end with values, that are between two other iterators. I know with non-constant iterators I can use the following syntax.

``````*begin = *result.begin();
*end = *result.end();
``````

But this will only change the values behind begin and end iterators

To be more precise. I have an initial vector

``````          {1, 2, 3, 4, 5, 6, 7}
^           ^
begin        end
``````

and some other vector called result, which contains

``````       {6, 6, 3, 5, 4, 13, 99}
^           ^
begin        end

``````

at the end I want my initial array to look like

``````       {6, 3, 5, 4, 5, 6, 7}
``````

by (31.9m points)

Using `std::copy()`, it can be done like this:

``````#include <iostream>
#include <vector>
#include <algorithm>

void printVector(const std::vector<int>& v) {
bool first = true;
std::cout << '{';
for (int i : v) {
if (!first) std::cout << ", ";
std::cout << i;
first = false;
}
std::cout << "}
";
}

int main(void) {
std::vector<int> v1 = {1, 2, 3, 4, 5, 6, 7};
std::vector<int> v2 = {6, 6, 3, 5, 4, 13, 99};

printVector(v1);
printVector(v2);

std::vector<int>::iterator dest_begin = v1.begin();
std::vector<int>::iterator src_begin = std::next(v2.begin(), 1);
std::vector<int>::iterator src_end = std::next(v2.begin(), 5);

std::copy(src_begin, src_end, dest_begin);

printVector(v1);

return 0;
}
``````

Output:

``````{1, 2, 3, 4, 5, 6, 7}
{6, 6, 3, 5, 4, 13, 99}
{6, 3, 5, 4, 5, 6, 7}
``````