lower_bound() function implement

#include<bits/stdc++.h>

using namespace std;

int Lower_Bound(int a[], int sz, int value)

{

    int low = 0, high = sz;

    while(low < high)

    {

        int mid = (low + high)/2;   /// also mid = low + (high-low)/2;

        if(a[mid] >= value)

            high = mid;

        else

            low = mid + 1;

    }

    if(low <= sz && a[low] < value)

        low++;

    return low;

}

int main()

{

    int n;

    cout << "Enter Array Size :: ";

    cin >> n;

    int a[n], value;

    cout << "Enter Ascending Order Array Element :: ";

    for(int i=0;i<n;i++)

        cin >> a[i];

    cout << "Enter Search Value :: ";

    cin >> value;

    int indx = Lower_Bound(a, n-1, value);

    if(indx >= n)

        cout << "Lower Bound Not Found." << "\n";

    else

        cout << "Lower Bound Found at " << indx << " index." << "\n";

    return 0;

}