[Valmont]

#include <iostream>

using namespace std; 

class String
{
private:
  friend int operator==(const String& lhs, const String& rhs);
  friend ostream& operator<<(ostream& os, String& s);
public:  
  String& operator=(const String&);
  String& operator+=(const String&);     

public:
  ~String ();
  String(const char* = "");
  String(const String&); 
private:
  char *m_pChars;
};

//Acts like a conversion operator: 'c-style char' to 'String'
String::String(const char *s) 
{
// need to copy the given string. If s is zero, make a null string!

  if (s)
  {  
    int len = strlen(s) + 1;
    m_pChars = new char[len];
    strcpy(m_pChars, s); 
  }
  else
  {
    m_pChars = new char[1];
    *m_pChars = '\0';
  }
}

String::String(const String& s)
{
  m_pChars = new char[strlen(s.m_pChars) + 1];
  strcpy(m_pChars, s.m_pChars);
} 

String::~String() { delete[] m_pChars; }

String& String::operator=(const String& s) 
{
  if (this != &s)
  {
    
    delete[] m_pChars; // first delete old
    int len = strlen(s.m_pChars) + 1;
    m_pChars = new char[len];
    strcpy(m_pChars, s.m_pChars);
  }  
  return *this;
} 

//MUST be defined outside class; So don't forget to make it a friend in the class that uses it.
ostream& operator<<(ostream& os, String& s)
{
  os<<s.m_pChars;
  return os; //Always return inserter/extractor.
}

int operator==(const String& lhs, const String& rhs) 
{ 
  return (strcmp(lhs.m_pChars,rhs.m_pChars) == 0); 
}

String& String::operator+=(const String& s)
{
  char* buffer = new char[strlen(m_pChars) + strlen(s.m_pChars) + 1]; 
  strcpy(buffer, m_pChars);
  strcat(buffer, s.m_pChars); 
  delete[] m_pChars;
  m_pChars = buffer;
  return *this;
} 

String operator+(const String& lhs, const String& rhs)
{
  String buffer(lhs); // calls copy ctor 
  buffer += rhs; // calls our overloaded +=
  return buffer;  
}

int main()
{
  String A("Hello! ");   
  A=A; //Test for self-assignment.
  
  String B="How are you?";
  cout<<("Hello! " == A)<<endl; //Hey... what's this? It works :)
  
  A+=B;
  cout<<A<<endl;

  return 0;
}