Question

Ie. I want to code a class ADT that can be used like this:

myADT <type> objectA;

in the same way that someone would use a vector like:

vector <type> aVector;

I’m guessing maybe it has something to do with templates and overloading the <> operator, but how do I get it to take a data type as an argument?

Answer 1

Let’s say you have a class that implements your ADT using a hard-coded typedef T:

class ADT
{
  public:
    typedef int T;

    ADT();
    T& operator[](size_t index);
    const T& operator[](size_t index) const;
    size_t size() const;
    ...
  private:
    T* p_;
    size_t size_;
};

(You have to work out the internal storage and member functions that are appropriate for your actual ADT).

To change this so that you can specify T as done for std::vector etc.:

template <typename T>    <-- specification of T moved to here
class ADT
{
  public:
                         <-- typedef for T removed from here
    ADT();
    T& operator[](size_t index);
    const T& operator[](size_t index) const;
    size_t size() const;
    ...
  private:
    T* p_;
    size_t size_;
};

Usage is then:

ADT<int> an_adt_int;
ADT<double> an_adt_double;