Реализация алгоритма find_firdt_not_of через другие алгоритмы

#include <iostream>
#include <algorithm>
#include <functional>
#include <cctype>
#include <vector>
using namespace std;
 
bool comp_case_insensitive (char c1, char c2) {
  return (tolower(c1)==tolower(c2));
}
 
int main () {
  int mychars[] = {'a','b','c','A','B','C'};
  vector<char> myvector (mychars,mychars+6);
  vector<char>::iterator it;
 
  int match[] = {'A','B','C'};
 
  it = find_first_of (myvector.begin(), myvector.end(),
                      match, match+3, comp_case_insensitive);
 
  if (it!=myvector.end())
    cout << "first match is: " << *it << endl;
    
  it = find_first_of (myvector.begin(), myvector.end(),
                      match, match+3, not2(ptr_fun(comp_case_insensitive)) );
 
  if (it!=myvector.end())
    cout << "first match is: " << *it << endl;
  
  return 0;
}

template <typename ForwardIterator1,
          typename ForwardIterator2>
 
ForwardIterator1 find_first_not_of( ForwardIterator1 first1, ForwardIterator1 last1,
                                    ForwardIterator2 first2, ForwardIterator2 last2 );

template <class ForwardIterator1, class ForwardIterator2>
ForwardIterator1 find_first_not_of ( ForwardIterator1 first1, ForwardIterator1 last1,
                                    ForwardIterator2 first2, ForwardIterator2 last2 )
{
    for ( ; first1 != last1; ++first1 )
        for (ForwardIterator2 it = first2; it != last2; ++it)
            if (*it != *first1) 
            {
                if (it == last2-1)
                    return first1;
            }
            else
                break;  
 
    return last1;
}

#include <iostream>
#include <algorithm>
 
template <class ForwardIter1, class ForwardIter2>
ForwardIter1 find_first_not_of(ForwardIter1 start1, ForwardIter1 stop1, ForwardIter2 start2, ForwardIter2 stop2){
    ForwardIter1 i;
    for ( i = start1; i != stop1; ++i )
        if ( std::find(start2, stop2, *i) == stop2 )
            break;
    return i;
}
 
int main(void){
    const int SIZE = 5;
    int arr1[SIZE] = { 1, 2, 3, 6, 5 };
    int arr2[SIZE] = { 1, 2, 3, 4, 5 };
    int * ptr;
    
    if ( ( ptr = (int*)find_first_not_of(arr1, arr1 + SIZE, arr2, arr2 + SIZE) ) == arr1 + SIZE )
        std::cout << "all elements from arr1 found in arr2" << std::endl;
    else 
        std::cout << "First element from arr1 that not found in arr2 is " << *ptr << std::endl;
    
    return 0;
}

    for ( ; start1 != stop1; ++start1 )
        if ( std::find(start2, stop2, *start1) == stop2 )

class Int
{
public:
   Int() : x( 0 ) {}
   explicit Int( int i ) : x( i ) {}
   bool operator ==( int i ) const
   {
      return ( x == i );
   }
private:
   int x;
};