Binary Search

Here’s something!

#include <iostream>
#include <vector>
using namespace std;

int binarySearch(vector<int> &arr, int x) {
    // Giving a starting point and an ending point
    int low = 0;
    int high = arr.size() - 1;
    //Do all of this, so long as we dont find anything or end
    while (low <= high) {
        int mid = low + (high - low) / 2;

        // See if x is present at mid
        if (arr[mid] == x)
            return mid;

        // If x greater, ignore left half
        if (arr[mid] < x)
            low = mid + 1;

        // If x is smaller, ignore right half
        else
            high = mid - 1;
    }

    // If we reach here, then element was not present
    return -1;
}

int main() {
    vector<int> arr = { 2, 3, 4, 10, 40 };
    int x = 10;
    int result = binarySearch(arr, x);
    if(result == -1) cout << "Element is not present in array";
    else cout << "Element is present at index " << result << "\n";
    return 0;
}

The whole point of a binary search is to search through data that’s already been sorted through. If it’s not already sorted, then there’s really no point to it.