binarySearch.cpp

// iterative
// binary search
#include <iostream>
#include <vector>
using namespace std;

int binarySearch(vector<int>arr, int n, int ele) {
    int l = 0, r = n-1;
    while(l<=r) {
        int mid = l + (r-l)/2;
        if(arr[mid] == ele)
            return mid;
        if(arr[mid] > ele) {
            r = mid-1;
        }
        else if(arr[mid] < ele) {
            l = mid+1;
        }
    }

    return -1;
}

int main()
{
    vector<int> arr;
    int n;
    cout<<"enter the size of the array:  ";
    cin>>n;
    cout<<"enter the elements in sorted order:  ";
    for(int i=0 ; i<n ; i++) {
        int a;
        cin>>a;
        arr.push_back(a);
    }
    sort(arr.begin(), arr.end());
    cout<<"Enter the element you want to search :  ";
    int ele;
    cin>>ele;
    int idx = binarySearch(arr,n,ele);
    cout<<"\n"<<idx<<"\n";

    return 0;
}