So in my class we just finished covering the topic of constructors and destructors. Now, my teacher has given us a lab where we have to create these classes and each of them must have a ctor/dtor. The problem I'm running into is..well.. it would be easier to describe in code :mrgreen:
here's what my main looks like:
class Database
{
public:
Database(char * file = "states.txt");
~Database(void);
void deleteDatabase ();
void fillDatabase ();
void insertDatabase (int index, State & tempState);
void printDatabase ();
private:
State * list; // array of states
int count; // total count of states
char * filename; // input filename
};class State
{
public:
State::State();
// State::State(char * name, int year, char * cap, int popRank);
State::~State();
void initState(char * tempName, int tempYear, char * tempCap, int tempPopRank);
void copyState(State & tempState);
void printState();
private:
char * name; // state name
int year; // year of entry into the union
char * cap; // state capital
int popRank; // population ranking
};int main(void)
{
Database db;
db.fillDatabase();
db.printDatabase();
return 0;
}and here's the fillDatabase function:
void Database::fillDatabase ()
{
char name[80]; // temp variables
int year; // to store
char cap[80]; // input data
int popRank; // from file
int index = 0; // index into array of State structs
char array[100]; // temporary storage for file input
State tempState;
// open file from filename field of db
// don't need to check for file open success because initDatabase already checked
ifstream inputFile( filename );
// loop through all the states
for ( int cnt = 0; cnt < count; cnt++ )
{
// read and parse one line of file into 4 input data fields
if ( !inputFile.eof() )
{
inputFile.getline( array, 100 );
if ( sscanf( array, "%[^,], %d, %[^,], %d", name, &year, cap,
&popRank ) == 4 )
{
// if tempState is created successfully from the 4 input data
// State tempState( name, year, cap, popRank );
tempState.initState(name, year, cap, popRank);
insertDatabase (index, tempState);
}
else
{
cout << "Error with file!" << '\n';
return;
}
index++;
}
}
// close file
inputFile.close();
}void Database::insertDatabase (int index, State & tempState)
{
// set pCurrent to location to be inserted in array
State * pCurrent = list + index;
// copy from state to pCurrent
pCurrent->copyState( tempState );
return;
}In this function i'm creating an instance of the tempState class to temporarily store data from the file and then copy the data into the db instance. The problem is that as soon as I leave this function, the destructor is invoked and deletes the last piece of data that the list was pointing to. How would I circumvent this problem (other than not creating a destructor)?
