C++ Tutorial/template/define iterator operator

Define class with iterator support and direct element access

<source lang="cpp">/* The following code example is taken from the book

* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/

1. include <algorithm>
2. include <functional>
3. include <iostream>
4. include <cstddef>

using namespace std;

/* PRINT_ELEMENTS()

* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/

template <class T> inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="") {

   typename T::const_iterator pos;
   std::cout << optcstr;
   for (pos=coll.begin(); pos!=coll.end(); ++pos) {
       std::cout << *pos << " ";
   }
   std::cout << std::endl;

}

template<class T, std::size_t thesize> class carray {

 private:
   T v[thesize];    // fixed-size array of elements of type T
 public:
   // type definitions
   typedef T        value_type;
   typedef T*       iterator;
   typedef const T* const_iterator;
   typedef T&       reference;
   typedef const T& const_reference;
   typedef std::size_t    size_type;
   typedef std::ptrdiff_t difference_type;
   // iterator support
   iterator begin() { return v; }
   const_iterator begin() const { return v; }
   iterator end() { return v+thesize; }
   const_iterator end() const { return v+thesize; }
   // direct element access
   reference operator[](std::size_t i) { return v[i]; }
   const_reference operator[](std::size_t i) const { return v[i]; }
   // size is constant
   size_type size() const { return thesize; }
   size_type max_size() const { return thesize; }
   // conversion to ordinary array
   T* as_array() { return v; }

}; int main() {

   carray<int,10> a;
   for (unsigned i=0; i<a.size(); ++i) {
       a[i] = i+1;
   }
   PRINT_ELEMENTS(a);
   reverse(a.begin(),a.end());
   PRINT_ELEMENTS(a);
   transform(a.begin(),a.end(),    // source
             a.begin(),            // destination
             negate<int>());       // operation
   PRINT_ELEMENTS(a);

}</source>

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