#include <iostream>

using namespace std;

const int FAIL = -1;
const int LENGTH = 100;

int comparisons;

int search(int data[], int length, int value);
int bsearch(int data[], int length, int value);
int bsearch_sub(int data[], int first, int last, int value);

int main() {
  int data[LENGTH];

  for (int i = 0; i < LENGTH; i++)
    data[i] = i+1;
  
  int value;
  int index;

  for (value = 5; value < LENGTH; value += 10) {

  cout << "** Linear search:" << endl;
  comparisons = 0;
  if ( (index = search(data, LENGTH, value)) != FAIL ) 
    cout << "Found " << value << " at index " << index << endl;
  cout << "search(): number of comparisons is " << comparisons << endl << endl;
  
  cout << "** Binary search:" << endl;
  comparisons = 0;
  if ( (index = bsearch(data, LENGTH, value)) != FAIL ) 
    cout << "Found " << value << " at index " << index << endl;
  cout << "bsearch(): number of comparisons is " << comparisons << endl << endl;

  }

  return 0;
}


int search(int data[], int length, int value) {
  for (int i = 0; i < length; i++) {
    comparisons++;
    if (data[i] == value)
      return i;
  }
  return FAIL;
}

int bsearch(int data[], int length, int value) {
  comparisons = 0;
  return bsearch_sub(data, 0, length-1, value);
}

int bsearch_sub(int data[], int first, int last, int value) {
  comparisons++;

  if (first > last)
    return FAIL;

  int mid = (first + last) / 2;

  if (data[mid] == value)
    return mid;
  else if (data[mid] > value)
    return bsearch_sub(data, first, mid-1, value);
  else // data[mid] < value
    return bsearch_sub(data, mid+1, last, value);
}