Example of the this Pointer

/************************************************************************
*

The following example shows code using class members without the this pointer. The comments on each line show the equivalent code with the hidden use of the this pointer.

                                                                        *
************************************************************************/

// This example uses class members without the this pointer.

#include <string.h>
#include <iostream.h>
class X
{
      int len;
       char *ptr;
public:
      int GetLen()          // int GetLen (X* const this)
      { return len; }       // { return this->len; }
      char * GetPtr()       // char * GetPtr (X* const this)
      { return ptr; }       // { return this->ptr; }
      X& Set(char *);
      X& Cat(char *);
      X& Copy(X&);
      void Print();
};

X& X::Set(char *pc)         // X& X::Set(X* const this, char *pc)
{
      len = strlen(pc);     // this->len = strlen(pc);
      ptr = new char[len];  // this->ptr =
                            //   new char[this->len];
      strcpy(ptr, pc);      // strcpy(this->ptr, pc);
      return *this;
}

X& X::Cat(char *pc)         // X& X::Cat(X* const this, char *pc)
{
      len += strlen(pc);    // this->len += strlen(pc);
      strcat(ptr,pc);       // strcat(this->ptr,pc);
      return *this;
}

X& X::Copy(X& x)            // X& X::Copy(X* const this, X& x)
{
      Set(x.GetPtr());      // this->Set(x.GetPtr(&x));
      return *this;
}

void X::Print()             // void X::Print(X* const this)
{
      cout << ptr << endl;  // cout << this->ptr << endl;
}
void main()
{
      X xobj1;
      xobj1.Set("abcd").Cat("efgh");
      // xobj1.Set(&xobj1, "abcd").Cat(&xobj1, "efgh");

      xobj1.Print();        // xobj1.Print(&xobj1);
      X xobj2;
      xobj2.Copy(xobj1).Cat("ijkl");
      // xobj2.Copy(&xobj2, xobj1).Cat(&xobj2, "ijkl");

      xobj2.Print();        // xobj2.Print(&xobj2);
}

/************************************************************************
*

This example produces the following output:

abcdefgh
abcdefghijkl

                                                                        *
************************************************************************/