algorithm

UC Library Extensions UnderC comes with a pocket implementation of the standard C++ libraries, wh

// UnderC Development Project, 2001
// First draft of some useful standard algorithms

#ifndef __ALGORITHM_H
#define __ALGORITHM_H
namespace std {

// until our template function resolution is a little more
// sophisticated, we just use specialized versions.
int min(int a, int b) { return a > b ? b : a; }
int max(int a, int b) { return a > b ? a : b; }
double min(double a, double b) { return a > b ? b : a; }
double max(double a, double b) { return a > b ? a : b; }


template <class IT, class T>
 IT find(IT start, IT finis, T val)
 {
   while (start != finis) {
     if (*start == val) return start;
     ++start;
   }
   return finis;
 }

template <class IT, class P>
 IT find_if(IT i1, IT i2, P pred)
 {
   while (i1 != i2) {
     if (pred(*i1)) return i1;
     ++i1;
   }
   return i2;
 }

template <class In, class Out>
  void copy(In i1, In i2, Out j) 
  {
    while (i1 != i2) {
      *j = *i1;
      ++j; ++i1;
    }
  }

template <class In, class Fn>
  void for_each(In i1, In i2, Fn fn)
  {
    while (i1 != i2) {
      fn(*i1);
      ++i1;
    }
  }

template <class In, class Out, class Fn>
  void transform(In i1, In i2, Out oi, Fn fn)
  {
    while (i1 != i2) {
      *oi = fn(*i1);
      ++i1; ++oi;
    }
  }

 template <class In, class T>
   int count(In i1, In i2, T val) 
   {
     int res = 0;
     while (i1 != i2) {
      if (*i1 == val) ++res;
      ++i1;
     }
     return res;
   }

 template <class In, class P>
   int count_if(In i1, In i2, P pred) 
   {
     int res = 0;
     while (i1 != i2) {
      if (pred(*i1)) ++res;
      ++i1;
     }
     return res;
   }

 
 template<class In, class Out, class Pr>
  void remove_copy_if(In i1, In i2, Out o, Pr fn)
  {
   while (i1 != i2) {
     if (! fn(*i1)) { *o = *i1; ++o; }
     ++i1;
   }
  }

 template<class In, class Pr>
  void remove_if(In i1, In i2, Pr fn)
  {
    i1 = find_if(i1,i2,fn);
    if (i1==i2) return i1;
    In ii = i1;
    ++ii;
    return remove_copy_if(ii,i2,i1,fn);
  }

template <class IT, class T>
 IT binary_search(IT low, IT end, T val)
 {
   IT high = end-1;
   while (low <= high) {
     IT mid = (low+high)/2;
     cout << mid << endl;
     if (val == *mid) return mid;
     if (val <  *mid) high = mid-1;
                else  low  = mid+1;
   }
   return end;
 }

template <class IT, class T>
  void fill(IT start, IT finish, T val)
  {
    while (start != finish) {
      *start = val;
      ++start;
    }
  }

template <class IT, class T>
  void fill_n(IT start, int n, T val)
  {
    for(int i = 0; i < n; i++) *start++ = val;
  }

template <class IT>
 IT min_element(IT i1, IT i2)
 {
   IT imin = i1;
   while (i1 != i2) {
     if (*i1 < *imin) imin = i1;
     ++i1;
   }
   return imin;
 }

template <class IT>
 IT max_element(IT i1, IT i2)
 {
   IT imax = i1;
   while (i1 != i2) {
     if (*i1 > *imax) imax = i1;
     ++i1;
   }
   return imax;
 }

template <class In, class T>
 void replace(In i1, In i2, T v1, T v2)
 {
   while (i1 != i2) {
     if (*i1 == v1) *i1 = v2;
     ++i1;
   }
 }

template <class C>
 class _back_inserter {
 private:
    C& m_container;
    C::value_type m_val;
  public:
   typedef C::value_type value_type;

   _back_inserter(C& c)
    : m_container(c)
    { }

  _back_inserter(const _back_inserter& c)
     : m_container(c.m_container)
    { }

   value_type&    operator*()
   { return m_val; }

  _back_inserter& operator++() 
   {
    m_container.push_back(m_val);
    return *this;
   }

 };

 template <class C>
   _back_inserter<C> back_inserter(C& c) {
       typedef _back_inserter<C> BI;
       //int i=0; //,j=1,k=2;
       BI bb(c);      
       //cout << i << ' ' << j << ' ' << k << endl;         
       return bb;
    }
 


 // should go in <numeric>
 template <class In, class T>
  T accumulate(In i1, In i2, T val)
  {
  // there's a bug in the list<T> postfix ++
      while (i1 != i2) { val = val + *i1; i1++; }
      return val;
  }

 // note: we don't have the iterator_traits mechanism,
 // so I've used the (experimental and non-standard) typeof operator.
 // These versions are of course only intended for numerical types.

 template <class In, class Out>
  Out partial_sum(In i1, In i2, Out j)
  {
     if (i1 == i2) return j;
     typeof(*i1) sum = 0;
     while (i1 != i2) {
        sum += *i1;
        *j = sum;
        ++i1; ++j;
     }
     return j;
  }

 template <class In, class Out>
  Out adjacent_difference(In i1, In i2, Out j)
  {
      if (i1 == i2) return j;
      typeof(*i1) sum = 0;
      while (i1 != i2) {
        *j = *i1 - sum;
        sum += *i1;
        ++i1; ++j;
      }
      return j;
  }

// *add 1.2.4 Simple Sort
template <class T>
 void swap(T& x, T& y) {
    T tmp = x;
    x = y;
    y = tmp;
  }

template <class It>
 void sort(It s, It e) {
   It f;
   for(; s != e; ++s) {
     f = s;
     ++f;
     for(; f != e; ++f) 
       if (*f < *s) swap(*f,*s);
   }
 }



}  // namespace std
#endif