#include <iostream>
#include <cstdlib>
#include <cmath>
using namespace std;

class Triangle
{
public:
    void setSide1(double arg)
    {
        side1 = arg;    // implicit inline function
    }
    void setSide2(double arg)
    {
        side2 = arg;
    }
    void setSide3(double arg)
    {
        side3 = arg;
    }
    void set(double,double,double);
    double getSide1() const
    {
        return side1;
    }
    double getSide2() const
    {
        return side2;
    }
    double getSide3() const
    {
        return side3;
    }
    double area() const;
private:
    double side1;
    double side2;
    double side3;
};


int main()
{
   Triangle t;
   t.setSide1(1.1);
   t.setSide2(1.2);
   t.setSide3(1.3);
   cout << t.getSide1() << endl;
   cout << t.getSide2() << endl;
   cout << t.getSide3() << endl;

   Triangle u;
   u.set(1.1,2.2,3.3);
   cout << u.getSide1() << endl;
   cout << u.getSide2() << endl;
   cout << u.getSide3() << endl;
   Triangle v;
   v.set(3,4,5);
   cout << v.area() << endl;

}

void Triangle::set(double a,double b,double c)
{
    side1 = a;
    side2 = b;
    side3 = c;
}

double Triangle::area() const
{
   double s = .5 * (side1+side2+side3); // semiperimeter
   return sqrt(s * (s-side1) * (s-side2) * (s-side3));
}