`new' will allocate memory for exactly one object of type `ClassA' and yield the address of the 1-st memory cell at which the definition of the object will start. In
Code:
ClassA *point;
point = 0;
you're not creating any object at all but just explictily stating that the pointer `point' will point to the zero-th cell. In that case your pointer merely becomes the so called `null pointer' - a special kind of pointers which do not point to any valid memory address.
I might err, so please correct me, if I'm wrong
---------- Post updated at 11:20 AM ---------- Previous update was at 11:20 AM ----------
as far as I remember, in
Code:
ClassA * point;
point = new ClassA;
`new' will allocate memory for exactly one object of type `ClassA' and yield the address of the 1-st memory cell at which the definition of the object will start. In
Code:
ClassA *point;
point = 0;
you're not creating any object at all but just explictily stating that the pointer `point' will point to the zero-th cell. In that case your pointer merely becomes the so called `null pointer' - a special kind of pointers which do not point to any valid memory address.
//intializing the pointer a NULL value...means pointing to nthing!
That's still not even valid C++ syntax. It will fail to build with compiler errors. You can't assign an integer to a pointer in C++ without a typecast.
Quote:
point = new ClassA();
//intializing the pointer value of the object of the Class A and hence ofcorse points to a valid memory!
Hello All,
I am a learner in C++. I was testing my inheritance knowledge with following piece of code.
#include <iostream>
using namespace std;
class base
{
public :
void display()
{
cout << "In base display()" << endl;
}
void display(int k)
{... (2 Replies)
I have the two class definition as follows.
class A { public: int a; };
class B : virtual public A{ };
The size of class A is shown as 4, and size of class B is shown as 16. Why is this effect ?. (2 Replies)
Hi all!
I am trying to register a device in an existing device class, but I am
having trouble getting the pointer to an existing class.
I can create a class in a module, get the pointer to it and then use
it to register the device with:
*cl = class_create(THIS_MODULE, className);... (0 Replies)
Hi,
I believe the next code is wrong:
class Egg {
Egg e;
int i;
Egg(int ii=0) : i(ii) {}
};
because you would end up with an endless definition (memory allocation) of Egg objects, thus int i.
Ok, so God Eckel proposes for a singleton:
class Egg {
static Egg e;
int... (5 Replies)
I'll be gratefull for any help. Thanks.
:)
This is the non class type error:
# g++ -I/usr/include/mysql -I/usr/include/mysql++ -lmysqlpp -L/usr/lib/mysql -L/usr/local/lib/mysql++ loaddsgsports.cpp -o loaddsgsports
loaddsgsports.cpp: In function âint outputToImport(const char*, const char*,... (1 Reply)
Hi, i have a question about C++. Is it possible to declare a class with a member ot the same class? For example, a linked list or i want to convert this C code to C++ class (Elemento)
typedef struct elemento
{
char name;
char value;
List<struct elemento> ltElementos;
... (7 Replies)
im just trying to have some fun and kill some time writing a c++ program that has a person type in a car make and model then gives them a year and a price. or something like that. i always have problems getting it goin but once the ball is rolling im usually pretty good. anyone wanna help me out? ... (1 Reply)
If one wants to get a start address of a array or a string or a block of memory via a function, there are at least two methods to achieve it:
(1) one is to pass a pointer-to-pointer parameter, like:
int my_malloc(int size, char **pmem)
{
*pmem=(char *)malloc(size);
if(*pmem==NULL)... (11 Replies)
Hi
We are using a code generator for initializing structures with the #define macro. Compiling it with the GCC 2.8.1 (with -ansi) it OK. But when we are using the SUN C 5.0 compiler it screams.
Following is a code sample:
#include <stdlib.h>
#include <stdio.h>
typedef struct TEST3 {... (4 Replies)
