Re: STL Link List Problem

From:
 cplusplusquestion@gmail.com
Newsgroups:
comp.lang.c++
Date:
Wed, 05 Sep 2007 23:44:31 -0000
Message-ID:
<1189035871.991596.298340@k79g2000hse.googlegroups.com>
On Sep 5, 9:06 pm, Barry <dhb2...@gmail.com> wrote:

Barry wrote:

cplusplusquest...@gmail.com wrote:

#include <iostream>
#include <list>

using namespace std;

struct Cell{
    list<int> vertices;
    bool counted;
    Cell* nextCell;
    Cell(){
        counted=false;
        nextCell=NULL;
    }
    ~Cell(){
        Cell* tmp = nextCell;
        Cell* current_ptr = nextCell;
        while(tmp != NULL){
            current_ptr = current_ptr->nextCell;
            delete tmp;


                        free(tmp);

calling delete will recursively call you ~Cell() and
std::vector<int>::~vector()

            tmp = current_ptr;
        }
    }
};

int main(){
    Cell* a = new Cell;
    Cell* b = new Cell;
    Cell* c = new Cell;
    a->nextCell = b;
    b->nextCell = c;
    delete a;
    return 0;
}

It compiles, but run the program, gets segmentation fault. If there is
no list<int> vertices, it will be fine. Or if no coding in destructor
and keep list<int> vertices, it's no problem too. Any idea?


so you're destructing vertices more than once within one Cell

std::vector<int> helping detect the error


sorry, list<int>
and moreover, if use *free* other than *delete*, then /vertices/ won't
be destructed, which causes memory leak

--
Thanks
Barry


Thanks! Does that mean I need to malloc() for each object instead of
new?

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