One more question on Memory allocation and operators overloading....

[incognito]

/* Ok I need help with this, I'll show you the main program and the constructor definition*/

int main()
{
String s1("initial test");
cout << "S1:\t" << s1.GetString() << endl;

char * temp = "Hello World";
s1 = temp;
cout << "S1:\t" << s1.GetString() << endl;

char tempTwo[20];
strcpy(tempTwo,"; nice to be here!");
s1 += tempTwo;
cout << "tempTwo:\t" << tempTwo << endl;
cout << "S1:\t" << s1.GetString() << endl;

cout << "S1[4]:\t" << s1[4] << endl;
s1[4]='x';
cout << "S1:\t" << s1.GetString() << endl;

cout << "S1[999]:\t" << s1[999] << endl;

String s2(" Another string");
String s3;
s3 = s1+s2;
cout << "S3:\t" << s3.GetString() << endl;

String s4;
s4 = "Why does this work?";
cout << "S4:\t" << s4.GetString() << endl;

return 0;
}

/* I need on this defintion, basically what is *this doing and what is assigned to what in terms of for example "s1" and '"s4" etc.*/

void String:perator+=(const String& rhs)
{
unsigned short rhsLen = rhs.GetLen();
unsigned short totalLen = itsLen + rhsLen;
String temp(totalLen);
unsigned short i;
for (i = 0; i<itsLen; i++)
temp[i] = itsString[i];
for (unsigned short j = 0; j<rhs.GetLen(); j++, i++)
temp[i] = rhs[i-itsLen];
temp[totalLen]='\0';
*this = temp;
}


THIS IS NOT THE WHOLE CODE

[matheo917]

i would be happy to explain this to you but i don't have that much time today... so i will just give a little taste today......

*this........is a pointer to an object (a function that is making a call)
for example...

int Sum = Addition(int One, int Two);

in this segment you are making a call to function Addition() and passing two parameters and the "result" the return value will be assigned to the "int Sum" .... in this case, inside the body of a Addtition() function, *this ... would be a pointer to the Addition() function itself...


in your example there's a lot to explain... from operator overloading to temporaries, constructor and copy constructor... and i am sorry i just don't have time today to answer it all...it is a very long discussion....

but nevertheless keep reading your book.... Jessy Liberty writes pretty good....

Good luck,

Regards,
matheo917

[incognito]

I pretty much know some about operator overloading, classes, constructors and all that, the problem is that I am a bit confused on the difference of "operator plus" and this "+=" that pretty much my consfusing there, I mean where is the this pointer return to, and things of that nature.

[Unregistered]

Im no authority but "this" is a pointer to the current object (whatever that may be).
When "this" is returned, it retuns the value of
whatever has focus at that point.