Re: Can 'this' be assigned a pointer to it?

From:
"Norman J. Goldstein" <normvcr@telus.net>
Newsgroups:
comp.lang.c++
Date:
Tue, 10 Mar 2015 22:59:19 -0700
Message-ID:
<mdoljn$ldd$1@speranza.aioe.org>
On 03/10/2015 10:29 PM, fl wrote:

Hi,

I read C++ for some time, but I still has problem in understand it.
Below is from web tutorial. It requires to debug it, but I cannot figure out
what is wrong with the void change function.

The error message says that this must be a lvalue. Does that mean 'this'
cannot be assigned a value? Then the change function is invalid?
What it wants me to do?

Please at least give a little hint on it.

thanks,

#include<iostream>
using namespace std;

class Test
{
private:
   int x;
public:
   Test(int x = 0) { this->x = x; }
   void change(Test *t) { this = t; }
   void print() { cout << "x = " << x << endl; }
};

int main()
{
   Test obj(5);
   Test *ptr = new Test (10);
   obj.change(ptr);
   obj.print();
   return 0;
}


There are a couple of things, here, that are confusing:
1. Overusing the variable name, 'x'. Change the declaration
of Test to be Test( int x0 = 0 );
2. The rules don't allow you to assign to "this". However, you
can pass around &obj and ptr inside the main function to change
which Test object you are working with.

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