binary_search.cpp

#include <iostream>
using namespace std;

int main() 

{
  int number_to_find = 7;
  int array[] = { 1, 3, 4, 6, 7, 8, 10, 13, 14, 18, 19, 21, 24, 37, 40, 45, 71 };
  int min = 0;
  int max = (sizeof(array) / sizeof(*array) - 1); // last index value 
  int guess;

  while (min <= max) 
  {
    guess = (int)(((max + min) / 2) + 0.5);
    if (number_to_find == array[guess]) 
      {
        cout << "The number is at index " << guess << endl;
        break;
      } else if (array[guess] < number_to_find) {
        min = guess + 1;
      } else {
        max = guess - 1;
      }
    cout << guess << endl;
  }

  return 0;
}