What is linear search in c++?

In the linear search algorithm, we compare each array element with the key until we find the matching key.

code for linear search

#include <iostream>
using namespace std;
// linear search
int linearSearch(int *arr, int n, int key)
{
    for (int i = 0; i < n; i++)
    {
        if (arr[i] == key)
        {
            return i;
        }
    }
    return -1;
}

int main()
{
    int arr[] = {1, 2, 3, 4, 5, 6, 7};
    int n = sizeof(arr) / sizeof(arr[0]);
    int key = 0;
    cin >> key;
    int index = linearSearch(arr, n, key);
    if (index != -1)
    {
        cout << "key is present at index :" << index << endl;
    }
    else
    {
        cout << "key is not present at any index :" << endl;
    }

    return 0;
}

Thanks for reading, have a good day! 👋