1

#include <iostream>
using namespace std;

int main()
{
	const float P = 3.1415;
	int r;

	cout << "vvedit radius: ";
	cin >> r;

	cout << "S = " << r * r * P;
	cout << "\nl = " << 2 * r * P;
}

2

#include <iostream>
using namespace std;

int main()
{
	int a = 1;
	int b = 2;
	int c = a;
	a = b;
	b = c;
}

int main1()
{
	int a = 1;
	int b = 2;
	a = a + b;
	b = a - b;
	a = a - b;
}

3

#include <iostream>
using namespace std;

int main()
{
	cout << "vvedit sumu(uah): ";
	float s;
	cin >> s;
	int r = (s - int(s)) * 100 + 0.5;
	cout << int(s) << " grn\t" << r << " kopijok";
}

4

#include <iostream>
using namespace std;

int main()
{
	cout << "vvedit chas(sek): ";
	int vvod;
	cin >> vvod;
	int d = vvod / 86400;
	int h = (vvod % 86400) / 3600;
	int m = (vvod % 3600) / 60;
	int s = vvod % 60;
	cout << d << " dniv, " << h << " hodyn, " << m << " hvylyn, " << s << " sekund";
}

7

#include <iostream>
using namespace std;

int main()
{
	int a;
	int b;

	cout << "vvedit pershe trycyfrove chyslo: ";
	cin >> a;

	cout << "vvedit druge trycyfrove chyslo: ";
	cin >> b;

	int mid_a = int((a / 10) % 10 * 10);
	int mid_b = int((b / 10) % 10 * 10);

	a = a - int((a / 10) % 10 * 10) + mid_b;
	b = b - int((b / 10) % 10 * 10) + mid_a;

	cout << a << '\n';
	cout << b;
}

8

#include <iostream>
using namespace std;

int main()
{
	int n;
	int m;
	int x;
	int g;

	cout << "k-ist kurok: ";
	cin >> n;
	cout << "cina kurky(grn): ";
	cin >> m;
	cout << "jajets z kurky na tyzhden: ";
	cin >> x;
	cout << "cina za 10 jajets(grn): ";
	cin >> g;

	int g_pdv = g - (g * 0.2);
	int total_cost = n * m;
	int per_day = (n * x / 7) * (g_pdv / 10);
	int to_payoff = (total_cost / per_day) + 0.51;

	cout << "okupnist: " << to_payoff << " dniv";
}