Binary Search

 #include <iostream>

using namespace std;

int binarySearch(int array[], int value, int low, int high) 

{

  while (low <= high) 

  {

    int mid = (low + high) / 2;

    if (value==array[mid])

    {

      return mid;

    }

    else

    {

     if (value<array[mid])

       high = mid - 1;

     else

       low = mid + 1;

}

  }

  return 0;

}

int main() {

  int array[] = {3, 4, 5, 6, 7, 8, 9};

  int value = 4;

  int n = sizeof(array) / sizeof(array[0]);

  int result = binarySearch(array, value, 0, n - 1);

  cout<<"Value found in index "<<result;

}