#include <iostream>
#include <type_traits>
#include <cmath>

using namespace std;

template <typename t1, typename t2>
class Triangle {
private:
    t1 a;
    t1 b;
    t1 c;
public:
    Triangle() {
        this->a = 0;
        this->b = 0;
        this->c = 0;
    }
    Triangle(int a, int b, int c) {
        this->a = a;
        this->b = b;
        this->c = c;
    }
    Triangle(t1 side) {
        this->a = side;
        this->b = side;
        this->c = side;
    }
    Triangle(const Triangle& t) {
        this->a = t.a;
        this->b = t.b;
        this->c = t.c;
    }

    friend ostream& operator<<(ostream& out, const Triangle t) {
        out << this->a << " " << this->b << " " << this->c << endl;
        return out;
    }

    t1 per() {
        cout << this->a + this->b + this->c << endl;
        return this->a + this->b + this->c;
    }
    t2 sqr() {
        int p = per() / 2;
        cout << sqrt(p * (p - this->a) * (p - this->b) * (p - this->c)) << endl;
        return sqrt(p * (p - this->a) * (p - this->b) * (p - this->c));
    }
};

int main() {
    setlocale(LC_ALL, "rus");
    Triangle<int, double> t1;
    Triangle<int, double> t2 = t1;
    cout << t1 << t2;

    Triangle<int, double> t3(4);
    Triangle<int, double> t4 = t3;
    cout << t3 << t4;

    Triangle<int, double> t5(3, 4, 5);
    Triangle<int, double> t6 = t5;
    cout << t5 << t6;
}