Thread: Trying to write to file...

This thing will not write to the file, please help!

Code:

/* Use data from keyboard to create a
   binary file of fixed length records */
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
struct info
   {
       char inv_num [16];
       char prod_name [21];
       char prod_code [4];
       int  oh_qty;
       int  bo_qty;
       int  oo_qty;
       float inv_eval;
       float avg_cost;
       float sell_price;
   };
 
class inventory

{
 protected:
 public:
        ofstream file;
 
inventory()
 {
        ofstream file("inventory.dat", ios::out | ios::app | ios::binary);
 }
 ~inventory()
 {
        file.close();
 }

void write_data(info &i)
{
        file.write((char*) &i,sizeof(i));
}
 
};
 
int main ()
{
        inventory go;
        info x;
 
        cout << endl << "Inventory Number: ";
        cin.getline (x.inv_num, 16);
        go.write_data(x);
        return 0;
}

Thanks!

Your constructor declares a new variable called file that goes out of scope when the constructor function ends. You want to construct the member variable with that information. To pass arguments to a constructor for a member variable use an initialization list:

Code:

inventory() : file("inventory.dat", ios::out | ios::app | ios::binary)
{
}