Использование виртуальных функций

#include <iostream>
#include <math.h>
using namespace std;
 
class Triangle
{
public:
    Triangle(float side = 0.0, float b = 0.0,
             float c = 0.0):
        sideA(side), angleB(b), angleC(c) { }
    void setSide(float s) { sideA = s; }
    void setAngleB(float b) { angleB = b; }
    void setAngleC(float c) { angleC = c; }
    float perimetr();
    float angleA();
    float sideB();
    float sideC();
    virtual void printParams();
 
protected:
    float sideA;
    float angleB;
    float angleC;
};
 
class EquilateralTriangle : public Triangle {
public:
    EquilateralTriangle(float side = 0.0, float b = 0.0,
                        float c = 0.0): Triangle(side, b, c) { }
    virtual void printParams();
};
 
int main()
{
    Triangle tr(23, 60, 45);
    EquilateralTriangle eqtr(4, 60, 60);
    tr.printParams();
    cout << endl;
    eqtr.printParams();
 
    return 0;
}
 
float Triangle::angleA()
{
    return (180.0 - (angleB + angleC));
}
 
float Triangle::sideB()
{
    return (sideA*sin(angleB*3.14/180))/sin(angleA()*3.14/180);
}
 
float Triangle::sideC()
{
    return (sideA*sin(angleC*3.14/180))/sin(angleA()*3.14/180);
}
 
float Triangle::perimetr()
{
    return sideA + sideB() + sideC();
}
 
void Triangle::printParams()
{
    cout << "Triangle:" << endl
         << "Sides: A = " << sideA << ", B = "
         << sideB() << ", C = " << sideC() << endl
         << "Angles: A = " << angleA() << ", B = "
         << angleB << ", C = " << angleC << endl
         << "Perimetr = " << perimetr() << endl;
}
 
void EquilateralTriangle::printParams()
{
    cout << "Equilateral Triangle:" << endl
         << "Side = " << sideA << endl
         << "Perimetr = " << perimetr() << endl;
}