Attempting to solve K&R exercise 3-1

binsearch.c

#include <stdio.h>
#include <stdlib.h>

int binsearch1(int, int[], int);
int binsearch2(int, int[], int);


int main(int argc, char *argv[]) 
{
  int size = atoi(argv[2]);
  int values[size];
  for(int i = 0; i < size; i++)
  {
    if (i != 0)
      values[i] = values[i-1] + (rand() % 20);
    else
      values[i] = 0;
    //printf("%d\n", values[i]);
  }
  int x = atoi(argv[1]);
  int v;
  if (atoi(argv[3]) == 1)
    v = binsearch1(x, values, size);
  else if (atoi(argv[3]) == 2)
    v = binsearch2(x, values, size);
  else 
  {
    printf("3rd arg must be 1 or 2\n");
    return 0;
  }
  printf("%d|%d\n", x, v);
  return 0;
}


int binsearch1(int x, int v[], int n) 
{
  int low, high, mid;
  low = 0;
  high = n -1;
  while (low <= high) 
  {
    mid = (low + high) / 2;
    if (x < v[mid])
      high = mid - 1;
    else if (x > v[mid])
      low = mid + 1;
    else /* found match */
      return mid;
  }
  return -1; /* no match */
}

int binsearch2(int x, int v[], int n) 
{
  int low, high, mid;
  if(x > v[n - 1] || x < v[0])
    return -1; /* it's not here */

  low = 0;
  high = n -1;
  int diff, olddiff;
  mid = (low + high) / 2;
  while (low <= high) 
  {
    diff = x - v[mid];
    if (diff == 0)
    {
      return mid;
    }
    else
    {
      mid += diff/2;
      if (olddiff == diff)
        return -1;
    }
    olddiff=diff;

  }
  return mid; /* low == high == mid */
}