How can I merge two vectors in C++ using STL?

How can I merge two vectors in C++ using STL?

You can use the std::merge function from the <algorithm> header to merge two sorted vectors.

Can you show me a code example?

Sure! Here's a simple example:

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

int main() {
    std::vector<int> vec1 = {1, 3, 5};
    std::vector<int> vec2 = {2, 4, 6};
    std::vector<int> merged(vec1.size() + vec2.size());

    std::merge(vec1.begin(), vec1.end(), vec2.begin(), vec2.end(), merged.begin());

    for (int num : merged) {
        std::cout << num << " ";
    }
    return 0;
}

What if the vectors are not sorted?

If the vectors are not sorted, you should sort them first using std::sort before merging.

Can you provide an example of sorting before merging?

Absolutely! Here's how you can sort the vectors before merging:

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

int main() {
    std::vector<int> vec1 = {5, 1, 3};
    std::vector<int> vec2 = {6, 2, 4};

    std::sort(vec1.begin(), vec1.end());
    std::sort(vec2.begin(), vec2.end());

    std::vector<int> merged(vec1.size() + vec2.size());
    std::merge(vec1.begin(), vec1.end(), vec2.begin(), vec2.end(), merged.begin());

    for (int num : merged) {
        std::cout << num << " ";
    }
    return 0;
}