runtime error, windows XP, borland C++ 5.5

[finnepower]

I really can't understand why this code genereates a runtime error. The program actually outputs the text in the file and then the error occurs. Thankful for help.

Oh, the file deck.txt looks like this:

diabolic edict#
circle of protection#
nantuko vigilante#

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

void add(vector<string> &rDeck, char *card);
void readfile(vector<string> &rDeck);

int main()
{
vector<string> deck;
readfile(deck);

cout<<deck.at(0);
cout<<deck.at(1);
cout<<deck.at(2);

return 0;
}

void add(vector<string> &rDeck, char *card)
{
string s;
s.assign(card);
rDeck.push_back(s);
}

void readfile(vector<string> &rDeck)
{
char *card;
string s;
ifstream fin;
fin.open("deck.txt");

	for(int i = 0;i < 3;i++)
	{
	fin.get(card, 40, '#');
	fin.ignore();
	add(rDeck, card);
	}

fin.close();
}

[JaWiB]

>>char *card;

Change that to:

char card[40];

[finnepower]

>>char *card;

Change that to:

char card[40];

Well that was easy, it works. Can you tell me why the error occured in the first place? I might learn something.

If you don't have time to do that: thanks anyway!

[JaWiB]

You were trying to copy information into unallocated memory on this line:

fin.get(card, 40, '#');

You either needed to dynamically allocate the pointer as an array, or statically size it (which made more sense since you are already limiting the length that you read from the file on that line)

Reading a good pointer tutorial might shed more light on the subject.

[finnepower]

I understand now, thanks. But why did the program still output the text correctly? Isn't that impossible?

[Daved]

The pointer pointed at some random place in memory, which just happened to allow you to modify it to hold the string you read from the file. You basically got lucky (or actually unlucky) that it was able to read in the string and not crash immediately.

By the way, is there a reasaon you aren't using getline to read into the string directly?

getline(fin, s, '#');

[finnepower]

By the way, is there a reasaon you aren't using getline to read into the string directly?

No, but this isn't a really important program so I use anything that works. But I'll keep that in mind next time. I use the program to shuffle a deck of cards and then draw a hand. It makes things easier if you want to find out statistics for the deck.