Programming Forums - Constructor Syntax help

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Constructor Syntax help

I've written code to search, add/remove items from a hashtable. My program compiles without errors, but it crashes with an access violation error(msvcr80d.dll!strcat...). I haven't found any solutions to that particular message, so I've decided to start with the constructors. I'd appreciate any suggestions. I cannot let this code defeat me! My professor tried to help me and finally suggested I see tutors. The tutor tried to help me for several hours and finally suggested the internet.
From stock.h:

 class stock

{

public:

stock(char const * const symbol, char const * const name, int sharePrice, date priceDate);                                          // sharePrice is given as a number of CENTS



stock(const stock& s);                // copy constructor

stock(void);                        // default constructor

char const * const getSymbol(void) const;

stock& operator=(const stock& s);

stock& operator=(stock const * const s);

~stock(void);

From stock.cpp:

stock::stock(char const * const symbol, char const * const name, int sharePrice, date priceDate):

    

    sharePrice(sharePrice),

    priceDate(priceDate)

{



    int length = strlen(symbol);

    this -> symbol = new char[length + 1];

    

    strcpy(this -> symbol,symbol);

    length = strlen(name);



    this -> name = new char[length + 1];

    strcpy(this -> name,name);

}



stock::stock(const stock& s):

    

    sharePrice(s.sharePrice),

    priceDate(s.priceDate)

    

        {

    //symbol = new char[strlen(symbol) + 1];

    strcpy(symbol,s.symbol);

    //name = new char[strlen(name) + 1];

    strcpy(name,s.name);

        }





stock& stock::operator=(const stock& s)

    

{

    cout << s.sharePrice;

    priceDate = s.priceDate;

    

    sharePrice = s.sharePrice;

    

        

    symbol = new char[strlen(symbol) + 1];

    strcpy(symbol,s.symbol);

    

    name = new char[strlen(name) + 1];

    strcpy(name,s.name);

    

    return *this;

}



stock& stock::operator=(stock const * const s)

{

    

        return *this;

}



stock::stock():

    symbol(symbol),

    name(name),

    sharePrice(sharePrice),

    priceDate(priceDate)

{

}

Re: Constructor Syntax help

In the code you've given, your copy constructor and assignment operators are among the obvious candidate culprits.

The assignment operator will need to be something like this;

stock &stock::operator=(const stock& s):    

 {

    sharePrice = s.sharePrice;

    priceDate = s.priceDate;

    delete [] symbol;

    delete [] name;    // avoid memory leak.  Note:  this assignment operator is not exception safe



    symbol = new char[strlen(s.symbol) + 1];

    strcpy(symbol,s.symbol);

    name = new char[strlen([color="RED"]s./color]name) + 1];

    strcpy(name,s.name);

    return *this;

}

and your copy constructor will, preferably, be something like this;

stock::stock(const stock& s):

    symbol(new char[strlen(s.symbol) + 1]),

    name(new char[strlen(s.name) + 1]),

    sharePrice(s.sharePrice),

    priceDate(s.priceDate)

{

    strcpy(symbol,s.symbol);

    strcpy(name,s.name);

}

The default constructor (the one with no arguments) is also a problem, as the non-static members are uninitialised, and you are using them to initialise themselves. That is formally undefined behaviour. If you really need such a constructor, provide more sensible default values.

It would probably be a good idea to use a std::string, rather than char * members, but that won't help you understand the problem you're having.

Re: Constructor Syntax help

What grumpy said (but with an extra '['). Also, is there any point to that last constructor which takes a pointer?

Re: Constructor Syntax help

Oh, bugger! One time when I wish to edit my post to make the content clearer, and can't.

Re: Constructor Syntax help

Thanks. After I corrected my constructors and copy consturctors, I was able to see all of my "other" compile errors. One of my copy constructor errors was that I had two copies.
Good times.