#include <iostream>
#include <fstream>
#include <iomanip>
#include <limits>
#include <cmath>
#include <stdlib.h>
using namespace std;

class SqrtException {};

static void first() {
	double a = -99, b = -99, per, area;
	cout << "\na, b, c, d: ";
	while (true) {
		cin >> a;
		if (!cin) {
			cin.clear();
			cout << "error" << endl;
			cin.ignore(numeric_limits<streamsize>::max(), '\n');
		}
		else {
			break;
		}
	}
	while (true) {
		cin >> b;
		if (!cin) {
			cout << "error";
			cin.clear(); // يà ٌëَ÷àé, هٌëè ïًهنûنَùèé ââîن çàâهًّèëٌے ٌ îّèلêîé
			cin.ignore(numeric_limits<streamsize>::max(), '\n');
		}
		else {
			break;
		}
	}
	per = 2 * (a + b);
	area = a * b;

	ofstream fout("lab8.txt");
	cout << setfill('#') << setprecision(5) << setw(15) << per << "\n";
	cout << setfill('#') << setprecision(5) << setw(15) << area;
	fout << setfill('#') << setprecision(5) << setw(15) << per << "\n";
	fout << setfill('#') << setprecision(5) << setw(15) << area;
	fout.close();

}

static void second() {
	double x;
	cout << "\n x: ";
	while (true) {
		cin >> x;
		if (!cin) {
			cout << "error";
			cin.clear();
			cin.ignore(numeric_limits<streamsize>::max(), '\n');
		}
		else {
			try {
				if (x <= 8) {
					throw SqrtException();
				}
				else
					break;
			}
			catch (SqrtException & s) {
				cout << "x > 8.\n";
			}
		}
	}

	cout << 12 * x + sqrt(x - 8);

}

int main() {
	cout << "//زا:\n//1.\tLp and Spr.\n"
		"//2.\tS=  ." << endl;

	first();
	second();
	return 0;
}