📅 Date: Jan 12, 2026
🔥 Topic: Basic Array Operation: Linear Search

🔍 What is Linear Search?

Today I wrote my first algorithm. The goal: Find if a specific number (key) exists in the array.

Logic: Check every element one by one. If it matches, Bingo! If the loop ends and we found nothing, the number isn't there.

💻 Day 12 Code: Search Engine V1

#include <iostream>
using namespace std;

int main() {
    int arr[] = {10, 50, 30, 70, 80, 20};
    int size = 6;
    int key;
    bool found = false;

    cout << "Enter number to search: ";
    cin >> key;

    for(int i = 0; i < size; i++) {
        if(arr[i] == key) {
            cout << "Found at Index: " << i << endl;
            found = true;
            break; // Stop searching once found
        }
    }

    if(!found) {
        cout << "Not Found!" << endl;
    }

    return 0;
}

💭 Thoughts

This is called O(n) complexity because in the worst case, I have to check every single number. Simple, but effective for small data.