//
// extremely simplified list-of-characters class --
//   example of defining a class based on a calling
//   program (use-list.cpp).
//

#ifndef CHAR_LIST_H_		// be sure we don't include 
#define CHAR_LIST_H_		//   this code twice.

#include <iostream>
#include <vector>

class char_list {

private:

  //implement using a vector of characters.
  vector<char> chars;

public:

  // a typedef for length, position.
  typedef vector<char>::size_type size_type;

  // constructors.
  char_list(void) { }		// needed for + operator.
  char_list(const char c) {
    chars.push_back(c);
  }
  char_list(const char *s) {
    for (int i = 0; s[i] != '\0'; ++i)
      chars.push_back(s[i]);
  }

  // length of list:
  // post:  returns number of characters in list.
  size_type length(void) const {
    return chars.size();
  }

  // += operator:
  // post:  c has been concatenated onto the current object.
  void operator+= (const char_list & c) {
    for (vector<char>::size_type i = 0; i < c.length(); ++i)
      chars.push_back(c.chars[i]);
  }

  // + operator:
  // post:  returns the concatenation of c1 and c2.
  friend char_list operator+ (const char_list & c1, const char_list & c2) {
    char_list temp;
    temp += c1;
    temp += c2;
    return temp;
  }

  // << operator:
  // post:  the characters in c have been printed to o.
  friend ostream & operator<< (ostream & o, const char_list & c) {
    for (vector<char>::size_type i = 0; i < c.length(); ++i)
      o << c.chars[i];
    return o;
  }

};

#endif // CHAR_LIST_H_