#include<stdio.h>
#define SIZE 1000000

void print_array(int a[], int);
int bsearch(int a[], unsigned int beg, unsigned int end, int val);

void main() {
  int A[SIZE], i;
  int pos = rand() % SIZE;
  printf("pos is %d\n", pos);
  A[pos] = 17;
  for (i = 1; (pos + i) < SIZE; i++)
    A[pos+i] = 17 + i;
  for (i = 1; (pos - i) >= 0; i++)
    A[pos-i] = 17 - i;
  pos = bsearch(A, 0, SIZE-1, 17);
  if (pos > -1)
    printf("17 occurs at position %d\n", pos);
  else 
    printf("17 does not occur\n");
}

int bsearch(int a[], unsigned int beg, unsigned int end, int val) {
  int mid;
  if (beg == end)
    if (a[beg] == val)
      return beg;
    else
      return -1;
  mid = (beg + end) / 2;
  if (val <= a[mid])
    return bsearch(a, beg, mid, val);
  else
    return bsearch(a, mid+1, end, val);
}

void print_array(int a[], int len) {
  int i;
  for (i = 0; i < len; i++)
    printf("%d ", a[i]);
  printf("\n");
}