Code snippet: inheritance with class templates and this->

A simple example how to use class templates in combination with inheritance.

A simple example how to use class templates in combination with inheritance. The this-> in the member function calculate of the class Rectangle becomes crucial, otherwise the compiler won’t find the location of the function.

#include <iostream>

using namespace std;

template<class dataType>
class Area
{
private:
    dataType area = 0.1;
public:
    void set_area(const float _area) {area = _area;};
    dataType get_area() const {return area;};
    void printArea() {cout << area << endl;};
};

template<class dataType>
class Rectangle : public Area<dataType>
{
public:
    void set_lengthA(const dataType _lengthA) {lengthA = _lengthA;}; 
    void set_lengthB(const dataType _lengthB) {lengthB = _lengthB;};
    void calculate() {this->set_area(lengthA * lengthB);};
private:
    dataType lengthA = 0.2;
    dataType lengthB = 0.2;

};

int main()
{
    Rectangle<float> myRect;
    myRect.set_lengthA(0.2);
    myRect.set_lengthB(0.3);
    myRect.calculate();
    myRect.printArea();
    return 0;
}