–If you want a object to be instantiated in a particular way (with the constructor which has arguments) : just declare/define an constructor that takes arguments and intializes the object in that particular way.

–YOU DO NOT NEED A PRIVATE CONSTRUCTOR FOR THAT

–look at the following code and try to compile it. it will give the following error. see that I did not declare a private constructor yet the compiler fails to compile as there exists a constructor with arguments.

#include
#include
#include
using namespace std;

enum CarSize{
        small = 0, medium = 1, large = 2
};

class RentalAccount{
        string accountNumber;
        string clientName;
        int age;
        float balance;

        public:
        // -- Constructor
        RentalAccount( const char* newAccountNumber,  const char* newClientName, const int newAge, const float newBalance = 0) { }

        // -- Set, and get Balance
        void SetBalance(const float newBalance);

        float GetBalance() const;

        // -- Calculate Balance
        void CalculateBalance(CarSize carSize);

        // -- Print Client information
        void Print() const;
};

int main()
{
        RentalAccount *C = new RentalAccount();

        return 1;
}

when you compile this - you will get the follwing error. Anyway the compiler is returning an error even though you I didn’t declare a private constructor, so I dont think a private constructor is needed to prevent somebody from instantiating an object using a plain constructor without any arguments. just declare a constructor with arguments and the compiler will do the rest.

cymkhat@cymkhat-laptop:~/cpp$ g++ cons.cpp
cons.cpp: In function ‘int main()’:
cons.cpp:35: error: no matching function for call to ‘RentalAccount::RentalAccount()’
cons.cpp:18: note: candidates are: RentalAccount::RentalAccount(const char*, const char*, int, float)
cons.cpp:10: note: RentalAccount::RentalAccount(const RentalAccount&)

my g++ version is

cymkhat@cymkhat-laptop:~/cpp$ g++ -v
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v –enable-languages=c,c++,fortran,objc,obj-c++,treelang –prefix=/usr –enable-shared –with-system-zlib –libexecdir=/usr/lib –without-included-gettext –enable-threads=posix –enable-nls –with-gxx-include-dir=/usr/include/c++/4.2 –program-suffix=-4.2 –enable-clocale=gnu –enable-libstdcxx-debug –enable-objc-gc –enable-mpfr –enable-targets=all –enable-checking=release –build=i486-linux-gnu –host=i486-linux-gnu –target=i486-linux-gnu
Thread model: posix
gcc version 4.2.3 (Ubuntu 4.2.3-2ubuntu7)

Second, before allocating memory in Init(), check to see if the pointer is non-NULL. If it’s non-NULL, then Init() has probably already been called, and no allocation is needed. If it’s NULL, then Init() can do the allocation.

Alex -

So what’s the correct way to handle the situation? Is it as simple as making sure to set the dynamic memory pointer to NULL (or to a valid address) before the Init() functions can be called?

Thanks!