Example: Insertion Sort in Ascending Order in C++

// Insertion Sort in Ascending Order
#include <iostream>
#include <vector> // Using vector for dynamic array, but can be done with raw array

void insertionSort(std::vector<int>& arr) {
    // Step 1: Iterate through the array starting from the second element
    // The first element (index 0) is considered already sorted by itself
    for (int i = 1; i < arr.size(); ++i) {
        // Step 2: Store the current element to be inserted
        int key = arr[i];
        // Step 3: Initialize 'j' to the index of the last element in the sorted part
        int j = i - 1;

        // Step 4: Move elements of arr[0...i-1], that are greater than key,
        // to one position ahead of their current position
        while (j >= 0 && arr[j] > key) {
            arr[j + 1] = arr[j]; // Shift element to the right
            j = j - 1;           // Move to the left in the sorted part
        }
        // Step 5: Place the key element at its correct position
        arr[j + 1] = key;
    }
}

int main() {
    // Step 1: Define an unsorted array
    std::vector<int> numbers = {12, 11, 13, 5, 6};

    std::cout << "Original array: ";
    for (int num : numbers) {
        std::cout << num << " ";
    }
    std::cout << std::endl;

    // Step 2: Call the insertion sort function
    insertionSort(numbers);

    // Step 3: Print the sorted array
    std::cout << "Sorted array (ascending): ";
    for (int num : numbers) {
        std::cout << num << " ";
    }
    std::cout << std::endl;

    return 0;
}