Question

hi guys im trying to transfer an older code from C to C++ for an assignment…. i have to implement a linked list by hand so I cannot use STL containers otherwise i’d already be done with this….

here’s my linked list:

#include <iostream> 
#include <string>
#include <fstream>
using namespace std;


struct Video { 
char video_name[1024];      //  video name
int ranking;                // Number of viewer hits
char url[1024];             //  URL
Video *next;  // pointer to Video structure
}  *head = NULL;        // EMPTY linked list

here is the read-in code:

void load()
{
struct Video *temp;
temp = (Video*)malloc(sizeof(Video)); //allocate space for node 
temp = head;
ifstream myfile ("Ranking.dbm");
if (myfile.is_open())
{
    string line;
    while ( myfile.good() )
    {

        myfile.getline(temp->video_name,1024);
        myfile >> temp->ranking;
        getline(myfile, line); // need to skip 'ranking's
                                // unread new-line
        myfile.getline(temp->url,1024);
        temp = temp->next; 

    }
    head = NULL;
    myfile.close();
}

else cout << "Unable to open file"; 

return ;

}

it is reading from a text file Ranking.dbm which looks like this:

bagheera
20
bagheera.com
sushi
60
sushi.com
wicket
99
wicket.com
teek
100
teek.com

basically each set of 3 lines should load into a Video structure which will be a new node in the linked list.

due to circustances beyond my control i am using XCode for this project. my question is why am I getting this error. I thought EXC_BAD_ACCESS was primarily an Objective-C error…?

Answer 1

In your load() function, you allocate a single node, read data to fill in the node, then assign temp = temp->next. However, temp->next is not initialized, so likely points to a random address.