3.cpp

#include <iostream>
using namespace std;

// Function for binary search
int binarySearch(int arr[], int size, int target) {
    int low = 0, high = size - 1;

    while (low <= high) {
        int mid = low + (high - low) / 2; // Prevent overflow
        if (arr[mid] == target) {
            return mid; // Target found
        } else if (arr[mid] < target) {
            low = mid + 1; // Target is in the right half
        } else {
            high = mid - 1; // Target is in the left half
        }
    }
    return -1; // Target not found
}

int main() {
    int arr[] = {2, 3, 4, 10, 40}; // Sorted array
    int size = sizeof(arr) / sizeof(arr[0]);
    int target;

    cout << "Enter the number to search: ";
    cin >> target;

    int result = binarySearch(arr, size, target);

    if (result != -1) {
        cout << "Element found at index " << result << endl;
    } else {
        cout << "Element not found." << endl;
    }

    return 0;
}