string to pointer

[vsachar]

Hi,
I'm writing an address into a file and later i need to read it and delete the memory at this address. I've copied this address into a character array and am having a lot of trouble trying to convert it back into a pointer.
The pointer initially (when writing to the file) was a void pointer.
Please help.

[JosAH]

Hi,
I'm writing an address into a file and later i need to read it and delete the memory at this address. I've copied this address into a character array and am having a lot of trouble trying to convert it back into a pointer.
The pointer initially (when writing to the file) was a void pointer.
Please help.

Cast your void pointer to a long (unsigned) int and write that number to a file. You can later read it back again and cast it to a void*.

kind regards,

Jos

[vsachar]

Hi,
I tried this. i don't know if thats what you meant but it didn't give me the output i was looking for

#include<iostream>
#include<string>
#include<stdio.h>
#include<fstream>
using namespace std;
void * operator new(size_t size)
{
	cout<<"\nOVERLOADED NEW";
	void * MemHandle;
	MemHandle=malloc(size);
	if(!MemHandle)
	{
		bad_alloc ba;
		throw ba;
	}
	ofstream out;
	out.open("D:/Project/abc.txt",ios::app);
	out<<"\n"<<(unsigned long int*)MemHandle;
	out.close();
	cout<<"\nmem handle:"<<MemHandle<<endl;
	return MemHandle;
}
void main()
{
	fstream in("D:/Project/abc.txt");
	int *p=new int;
	char buf[20];
	in.getline(buf,8);
	buf[8]='\0';
	cout<<"buf:"<<(unsigned long int*)buf;
}

The output was :

OVERLOADED NEW
mem handle:003552A0
buf:0012FE9


i needed the buf to hold the initial value.
Please help and Thanks in advance.

[JosAH]

Don't do it like that; do something like this instead for your output:

void* memory_pointer= ...;
cout << (unsigned long)memory_pointer;

and for input do something like this:

unsigned long tmp;
void* memory_pointer;
cin >> tmp;
memory_pointer= (void*)tmp;

kind regards,

Jos

[vsachar]

Don't do it like that; do something like this instead for your output:

void* memory_pointer= ...;
cout << (unsigned long)memory_pointer;

and for input do something like this:

unsigned long tmp;
void* memory_pointer;
cin >> tmp;
memory_pointer= (void*)tmp;

kind regards,

Jos

Thank you so much!!
It worked!
:)