C42 Answer

/* Puzzle C42 -- find the first element of one array that is not in another
|
|  The function returns the <strong>index</strong> of the first
|  element of the first array that is not also in the second array.
|  If all elements of the first array are also in the second array,
|  return -1.
*/
int allPresent( int arrA[], int sizeA, int arrB[], int sizeB )
{
  int j, k, current;
  
  /* check the elements in the first array one by one */
  for ( j=0; j<sizeA; j++ )
  {
    current = arrA[j];
    
    /* find the first array's element in the second array */
    k = 0;
    while ( k<sizeB && current != arrB[k] )
      k++ ;

    /* return the index of the first element in arrA not in arrB */
    if ( k==sizeB ) return j;
  }
  
  /* if all the elements in arrA are present in arrB, return -1 */
  return -1;
}