lab6

#include <iostream>
#include <cmath>

using namespace std;

void task3()
{
  cout << "task(a)" << endl;
  const int size = 15;
  int i = 0;
  double arr[size];
  for (i = 0; i < size; i++)
  {
    arr[i] = rand() % 10 * 0.1;
    cout << arr[i] << "   ";
  }
  cout << endl << endl;
  cout << "task(b)" << endl;
  for (i = 0; i < size; i++)
  {
    arr[i] = rand() % 10 * 0.1 + 22;
    cout << arr[i] << "   ";
  }
  cout << endl << endl;
  cout << "task(c)" << endl;
  for (i = 0; i < size; i++)
  {
    arr[i] = rand() % 100 * 0.1;
    cout << arr[i] << "   ";
  }
  cout << endl << endl;
  cout << "task(d)" << endl;
  for (i = 0; i < size; i++)
  {
    arr[i] = rand() % 1000 * 0.1 - 50;
    cout << arr[i] << "   ";
  }
  cout << endl << endl;
  cout << "task(e)" << endl;
  for (i = 0; i < size; i++)
  {
    arr[i] = rand() % 11;
    cout << arr[i] << "   ";
  }
  cout << endl << endl;

}
void task38()
{
  const int size = 10;
  int arr[size];
  int t;
  cout << "Our array : ";
  for (int i = 0; i < size; i++)
  {
    arr[i] = i + 1;
    cout << arr[i] << "  ";
  }
  cout << endl << endl;
  for (int i = 0; i < size; i++)
  {
    if (i % 2 == 0 && i < 9)
    {
      swap(arr[i], arr[i + 1]);
    }
  }
  for (int i = 0; i < size; i++)
  {
    cout << arr[i] << "  ";
  }
  cout << endl << endl;
}
void task73()
{
  int a = 0, k;
  double n;
  double arr[15];
  double m[15];
  for (int i = 0; i < 15; i++)
  {
    a += 5;
    arr[i] = a * 0.1;
    cout << arr[i] << "  ";
  }
  cout << endl;
  cout << "Enter n :";
  cin >> n;
  double c, p, l=0, e = 0;
  p = abs(n - arr[0]);
  for (int i = 0; i < 15; i++)
  {
    c = abs(n - arr[i]);
    if (c < p)
      l = i, e = arr[i];
    p = c;
  }
  cout << endl;
  cout << "Number is " << l + 1 << " Znachenie is " << e;
  cout << endl << endl;
}

void task108()
{
  int arr[7];
  for (int i = 0; i < 7; i++)
  {
    arr[i] = rand() % 10;
    if (i == 6)
    {
      arr[i] = pow(arr[0], 2);
    }
    cout << arr[i] << "  ";
  }
  cout << endl << endl;
}

void task143()
{
  int kx, ky;
  int x[30];
  int y[30];
  double maxX = x[0];
  double maxY = y[0];
  double distancex, distancey, distance;
  for (int i = 0; i < 30; i++)
  {
    x[i] = rand() % 20 - 10;
    y[i] = rand() % 20 - 10;
  }
  for (int i = 0; i < 30; i++)
  {
    for (int n = 0; n < 30; n++) {
      distancex = (pow(x[i] - x[n], 2));
    }
    if (distancex > maxX)
    {
      maxX = x[i];
      kx = i++;
    }
    for (int n = 0; n < 30; n++) {
      distancey = (pow(y[i] - y[n], 2));
    }
    if (distancey > maxY)
    {
      maxY = y[i];
      ky = i++;
    }
  }
  distance = sqrt(distancex + distancey);
  cout << "Number point x:" << kx << "   " << "Number point y:" << ky << endl;
  cout << "Distance : " << distance << endl;
}

void task178()
{
  int long n = 0, a = 0, b = 1, factN = 1;
  cout << "Enter n : ";
  cin >> n;
  int* arr = new int[n];
  for (int i = 0; i < n; i++)
  {
    arr[i] = rand() % 10 + 1;
    if (i == n - 1) arr[i] = n;
    cout << arr[i] << "    ";
  }
  cout << endl << endl;
  for (int i = 0; i < n; i++)
  {
    b *= arr[i];
  }
  for (int k = 2; k <= n; k++)
  {
    factN *= k;
  }
  cout << b << "  " << factN << endl;
  if (b == factN)
  {
    cout << "is a permutation of natural numbers";
  }
  else cout << "is not a permutation of natural numbers";
}
int main()
{
  system("cls");
  int number;
tryagain:
  cout << "Numbers of the tasks: 3, 38, 73, 108, 143,178" << endl;
  cout << "Enter number of the task(enter 0 to exit)..." << endl;
  cin >> number;
  switch (number)
  {
  case(3):
  {
    task3();
    goto tryagain;
  }

  case(38):
  {
    task38();
    goto tryagain;
  }

  case(73):
  {
    task73();
    goto tryagain;
  }

  case(108):
  {
    task108();
    goto tryagain;
  }

  case(143):
  {
    task143();
    goto tryagain;
  }

  case(178):
  {
    task178();
    goto tryagain;
  }

  case(0):
  {
    return 0;
    break;
  }
  default:
  {
    cout << "Invalid number" << endl;
    goto tryagain;
  }
  }
}