Thread: i get error message

hello im new to c++ and im trying out this exercise from a book where i have to convert list of char* to c style strings then convert it to a vector of strings.
here's the code:

Code:

#include "stdafx.h"
#include <iostream>
#include <string>
#include <vector>
#include <list>

using namespace std;

int main()
{
	list<char*> c;
	c.push_back("hi");
	c.push_back("fu");
	c.push_back("ga");
	vector<string> sv;
	char** c2=new char*[c.size()];

       
	for (int i=0; i < 2; i++)
		c2[i]=new char[2];
        // convert to c style strings
	for (list<char*>::iterator j=c.begin(); j!=c.end(); ++j)
	{
		static int i=0;
		c2[i]=*j;
		++i;
	}
        // convert to vector of strings
	for (char**p=c2; p < c2+c.size(); ++p)
		sv.push_back(*p);
  
	for (vector<string>::iterator i=sv.begin(); i!=sv.end(); ++i)
		cout << *i << endl;
        // the codes below seem to cause the problem. i use free version of visual c++ and when i exclude the code below, the program runs fine. 
	for (int i=0; i<c.size(); ++i)
		delete []c2[i];
	delete [] c2;
	system("pause");
	return 0;
}

visual c++ generates an error message:
Debug Assertion Failed!
Expression: _BLOCK_TYPE_IS_VALID(pHead->nBlockUse)

Originally Posted by Drogin

or like this, in "c-style":

Code:

char test[3];
test[0] = 'H';
test[1] = 'i';
test[2] = '\0';

Now, it's vital you remember to add that \0 at the end, or else, functions will have trouble understanding where your string ends

Or more commonly...

Code:

char test[] = "Hi";

Your for loop is overwriting the memory you allocated with the pointer in the list. This is a memory leak. Later when you try and delete[] the memory, you are actually trying to delete the pointers stored in the list.

I'm not sure if this is being done for an assignment, but why not use std::string instead of char* in your program?

Also, you are not allocating enough memory in the first place. You need to add an extra byte for the null terminator. Then fix your bug by changing this

Code:

c2[i]=*j;

to this

Code:

strcpy(c2[i], *j);