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Writing To a File in Binary Mode

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Join Date: Aug 2008

Posts: 15

Reputation: mksakeesh is an unknown quantity at this point

Solved Threads: 0

mksakeesh

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Newbie Poster

Re: Writing To a File in Binary Mode

#11

Aug 13th, 2008

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Originally Posted by Ancient Dragon

>>I have used char *per because 'write' function only accepts pointer to character.
False. You can put anything you want to there -- just typecast it to char*

But you still failed to correct the problem. per is still an unallocated pointer which will crash your program.

Thanks ...... this is working now; i changed the program like this

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#include<fstream.h>
#include<iostream.h>
#include<string.h>
using namespace std;
class emp
{
	public:
		char *per;
		void write()
		{		
			ofstream out("ss.txt",ios::app | ios::binary);
			cout<<"Enter some character ....\n";
			per = new char[100];
			cin>>per;
			//out.write(per,sizeof(per));
			out.write(per,strlen(per));
 
		}
 
};
 
void main()
{
	emp e;
	e.write();
 
}
#include<fstream.h>
#include<iostream.h>
#include<string.h>
using namespace std;
class emp
{
	public:
		char *per;
		void write()
		{		
			ofstream out("ss.txt",ios::app | ios::binary);
			cout<<"Enter some character ....\n";
			per = new char[100];
			cin>>per;
			//out.write(per,sizeof(per));
			out.write(per,strlen(per));

		}
		
};

void main()
{
	emp e;
	e.write();
	
}

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Join Date: May 2008

Posts: 374

Reputation: Clockowl is on a distinguished road

Solved Threads: 27

Clockowl

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Posting Whiz

Re: Writing To a File in Binary Mode

#12

Aug 13th, 2008

EDIT: Didn't see the new[] Ouch. My bad, 100%.

Job well done on the program. However, when write is now called multiple times, each time it will allocate 100 bytes of memory to the pointer. This is called a memory leak. To fix that, make sure you only allocate the memory once (call new once).

Last edited by Clockowl; Aug 13th, 2008 at 11:44 am.