Practice5

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

void task4()
{
	int a3 = 0, a4 = 0, a5 = 0, a6 = 0;
	for (int i = 1; i <= 100; i++)
	{
		if (i % 3 == 1)
			a3++;
		if (i % 4 == 2)
			a4++;
		if (i % 5 == 3)
			a5++;
		if (i % 6 == 4)
			a6++;
	}
	cout << "amount of n%3=1 is" << a3 << "\namount of n%4=2 is" << a4 << "\namount of n%5=3 is" << a5 << "\namount of n%6=4 is" << a6;
	cout << endl << endl;
}

void task39()
{
	int fibonacci[41] = { 1, 1 };
	for (int i = 2; i <= 40; i++)
	{
		fibonacci[i] = fibonacci[i - 1] + fibonacci[i - 2];
	}
	cout << "40th number of Fibonacci is" << " " << fibonacci[40] << endl << endl;
}

void task74()
{
	int n, denominator = 1;
	double x, sum = 1;
	cout << "input 'x', then '1 < n <= 10'" << endl;
	cin >> x >> n;

	int *power = new int[n];
	if (n > 1 && n <= 10)
	{
		for (int j = 0; j < n; j++)
		{
			power[j] = j + 1;
		}

		for (int i = 0; i < n; i++)
		{
			denominator *= power[i];
			sum += pow(x, power[i]) / denominator;
		}
		cout << sum;
	}
	else cout << "n doesn't fit the condition";
	cout << endl << endl;
}

void task109()
{
	cout << "pow(x, 2) + x + 17, 0 <= x <= 15" << endl;
	int result, divider = 2;
    for (int i = 0; i <= 15; i++)
	{
		result = pow(i, 2) + i + 17;
		cout << result;
		while (result % divider != 0 && divider < result / 2)
		{
			divider++;
		}
		if (result % divider != 0)
			cout << " " << "is simple";
		cout << endl;
	}
	cout << endl;
}

void task144()
{
	int a, b, c, a2;
    for (a = 1; a < 25; a++)
	{
		for (b = 1; b < 25; b++)
		{
			for (c = 1; c < 25; c++)
			{
				if (a * a + b * b == c * c)
					cout << a << " " << b << " " << c << endl;
			}
		}
	}
	cout << endl;
}

void task179()
{
	int sequence[10] = { 1, 1, 2, 3, 10, 4, 5, 6, 10, 0 }, amount = 1;
	for (int i = 0; i < 10; i++)
	{
		if (sequence[i] == sequence[i + 1])
			amount++;
	}
	for (int j = 0; j < 10; j++)
	{
		cout << sequence[j] << " ";
	}
	cout << endl << "amount=" << amount << endl << endl;
}

void task214()
{
	double aCurrent = 0.5, aPrevious, e; 
	int number = 1;
	cout << "Input e..." << endl;
	cin >> e;
	cout << aCurrent;
	do
	{
		aPrevious = aCurrent;
		aCurrent = 1 / 2 * cos(aPrevious);
		cout << " " << aCurrent;
		number++;
	} while (abs(aCurrent - aPrevious) >= e);
	cout << endl << number << endl << endl;
}

void task249()
{
	cout << setw(5) << "x:" << setw(10) << "y:" << endl;
	double y;
	for (double i = 0; i <= 23; i += 0.5)
	{
		y = i / cos(i);
		cout << setw(5) << i << setw(10) << y << endl;
	}
	cout << endl;
}

int main()
{
	int number;
	int a = 1;
	cout << "Numbers of tasks are 4, 39, 74, 109, 144, 179, 214, 249 " << endl;
	while (a == 1)
	{
		cout << "Input the number of the task (0 to close the program)..." << endl;
	tryagain:
		cin >> number;
		cout << endl;

		if (number == 4)
			task4();
		else if (number == 39)
			task39();
		else if (number == 74)
			task74();
		else if (number == 109)
			task109();
		else if (number == 144)
			task144();
		else if (number == 179)
			task179();
		else if (number == 214)
			task214();
		else if (number == 249)
			task249();
		else if (number == 0)
			a = 0;
		else 
		{ 
			cout << "Incorrect number, try again..." << endl; goto tryagain; 
		}
	}
}