main.cpp

#include <iostream>
#include <math.h>
#define P 3.14
using namespace std;

int main() {

int a = 0, b = 0, c = 0, d = 0, r = 0, d1 = 0, p1 = 0, s1 = 0, p2 = 0, s2 = 0, s3 = 0, s4 = 0, g = 0, h = 0, k = 0;
double p = 0, s = 0;
cout << "                   menu \n";
cout << "select"" to number: \n";
cout << "1-colculation perimeter \n";
cout << "2-colculation area \n";
cout << "3-calculation of the possibility of the existence of a triangle \n";
cin >> h;
if (h < 1)
{
    cout << "incomprehensible query, enter again";
    cin >> h;
}
if (h > 3)
{
    cout << "incomprehensible query, enter again";
    cin >> h;
}
switch (h)
{
case 1:
    cout << "you chose 1-perimeter \n";
    cout << "now you need to choose which shape you need to find the perimeter \n";
    cout << "---------------------------------------- \n";
    cout << "1-colculation perimeter quadrilateral \n";
    cout << "2-colculation perimeter circle \n";
    cout << "3-colculation perimeter triangle \n";

    cin >> k;
    if (k < 1)
    {
        cout << "incomprehensible query, enter again \n";
        cin >> k;
    }
    if (k > 3)
    {
        cout << "incomprehensible query, enter again \n";
        cin >> k;
    }
    switch (k)
    {
    case 1:
        cout << "you chose 1-quadrelateral \n\n";
        cout << "now enter lenght a \n";
        cin >> a;
        cout << "enter width b \n";
        cin >> b;
        p2 = (a * 2) + (b * 2);
        cout << "perimeter quadrelateral = " << p2;
        break;

    case 2:
        cout << "you chose 2-circle \n\n";
        cout << "now enter radius \n";
        cin >> r;
        p = 2 * P * r;
        cout << "perimeter circle = " << p;
        break;

    case 3:
        cout << "you chose 3-triangle \n\n";
        cout << "now enter 1 side \n";
        cin >> a;
        cout << "enter 2 side \n";
        cin >> b;
        cout << "enter 3 side \n";
        cin >> c;
        p2 = a + b + c;
        cout << "perimeter triangle = " << p2;
        break;
    }
    break;



case 2:
    cout << "you chose 2-area \n";
    cout << "now you need to choose which shape you need to find the area \n";
    cout << "---------------------------------------- \n";
    cout << "   1-colculation area quadrilateral \n";
    cout << "   2-colculation area circle \n";
    cout << "   3-colculation area triangle \n";


    cin >> d;
    if (d < 0)
    {
        cout << "incomprehensible query, enter again \n";
        cin >> d;
    }
    if (d > 3)
    {
        cout << "incomprehensible query, enter again \n";
        cin >> d;
    }
case 3:
    cout << "you chose 2-possibility of existence \n";
    cout << "-------------------------------- \n";
    cout << "now enter 1 side \n";
    cin >> a;
    cout << "enter 2 side \n";
    cin >> b;
    cout << "enter 3 side \n";
    cin >> c;
    if((a < b+c) and (b < a+c) and (c < a+b))
    {
       cout << "the triangle exists";
    }
        else
    {
        cout << "the triangle doesnt exists";
    }
}
switch (d)
{


case 1:
    cout << "you chose 1-quadrilateral \n";
    cout << "select to number: \n";
    cout << "1-colculation area square \n";
    cout << "2-colxulation area rectengle \n";
    cin >> g;
    if (g < 1)
    {
        cout << "incomprehensible query, enter again";
        cin >> g;
    }
    if (g > 2)
    {
        cout << "incomprehensible query, enter again";
        cin >> g;
    }

    switch (g)
    {
    case 0:
        cout << "you chose 0-square \n";
        cout << "enter 1 side \n";
        cin >> a;
        s = a * a;
        cout << "area square = " << s;
        break;

    case 1:
        cout << "you chose 1-rectengle \n";
        cout << "enter lenght a \n";
        cin >> a;
        cout << "enter width b \n";
        cin >> b;
        s = a * b;
        cout << "area rectangle = " << s;
        break;
}
case 2:
    cout << "you chose 2 \n";
    cout << "enter radius R \n";
    cin >> r;
    s = P * r * r;
    cout << "area circle = " << s;
    break;

case 3:
    cout << "you chose 4 \n";
    cout << "enter 1 side \n";
    cin >> a;
    cout << "enter 2 side \n";
    cin >> b;
    cout << "enter 3 side \n";
    cin >> c;
    p2 = a + b + c;
    p = (double)p2 / 2;
    s = sqrt(p * (p - a) * (p - b) * (p - c));
    cout << "area triangle = " << s;
    break;

}
return 0;
}