Question

I am working on an assignment in C++, a language I am not particularly proficient in.

I am attempting to declare a dynamic array of ‘Account’ objects in a file main.cpp:

Account * acctArray = new Account[];

main.cpp includes Account.h:

class Account {
private:
    int customerID;
    int BSB;
    int acctNumber;
    string surname;
    string firstName;
    double balance;
    double withdrawn;
public:
    Account() {};
    //setters
    void setCustID(int ID);
    void setBSB(int inBSB);
    void setAcctNo(int number);
    void setSurname(string sname);
    void setFirstName(string fname);
    void setBalance(double bal);
    void setWithdrawn(double withd);
    //getters
    //(snipped for irrelevance)
    //methods
    bool withdraw(double amount);
};

However, when compiling on my uni’s unix machine (the machine the assignment must be submitted on), I get the following error:

“main.cpp”, line 130: Error: The type “Account[]” is incomplete.

I tried compiling with

Account * acctArray = new Account[5];

to see if I could isolate the problem, and this line compiled fine.

What am I doing wrong?? I fear the solution lies in pointers/references and my lack of understanding thereof.

Answer 1

An array in C++ has a fixed size. There is no built-in “dynamic array” functionality. If you want a dynamic array, use a std::vector<Account>.

I am working on an assignment in C++, a language I am not particularly proficient in.

It is best to avoid new and explicit dynamic allocation wherever possible. If you think you need to dynamically allocate something using new and manage it yourself, there’s probably a better way to accomplish the task.