#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;
}