Example: Merge Two Sorted Arrays (STL std::merge) in C++

// Merge Two Sorted Arrays (STL std::merge)
#include <iostream>
#include <vector>
#include <algorithm> // Required for std::merge

int main() {
    // Step 1: Define the two sorted input vectors
    std::vector<int> arr1 = {1, 3, 5, 7, 9};
    std::vector<int> arr2 = {2, 4, 6, 8, 10, 12};

    // Step 2: Create a destination vector with enough capacity
    // It should be large enough to hold all elements from both source vectors
    std::vector<int> merged_arr(arr1.size() + arr2.size());

    // Step 3: Use std::merge to combine the elements
    // Parameters:
    //   - arr1.begin(), arr1.end(): Input range 1
    //   - arr2.begin(), arr2.end(): Input range 2
    //   - merged_arr.begin(): Output iterator where the merged elements will be stored
    std::merge(arr1.begin(), arr1.end(),
               arr2.begin(), arr2.end(),
               merged_arr.begin());

    // Step 4: Print the merged array
    std::cout << "Merged array using std::merge: ";
    for (int val : merged_arr) {
        std::cout << val << " ";
    }
    std::cout << std::endl;

    return 0;
}