Question

Write a C++ program which has a main-driver and
creat a polygon class Poly which has an array of n pairs of floats, x[i] and y[i],
creat a derived class Triangle,  
creat a derived class Quadrilateral class (which you may assume is convex and points given clockwise)
You need to compute the area for the two derived classes
but use inheritance to compute perimeter in all these classes.
Constructors, accessors, mutators, and anything else needed should be written too.

Make sure to request points at constructor time in the driver.
The driver should show a menu like: P for Polygon, T for Triangle, and Q for Quadrilateral.
After recieving the data, the driver should print the perimeter and area.

Answer 1

ScreenShot

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Program

//Header files
#include<iostream>
#include <iomanip>
using namespace std;
//Base class poly
class poly {
   //Member variables
public:
   int n;
   float *x,*y;
  
   //Constructor
   poly(int size) {
       n = size;
       x=new float[n];
       y=new float[n];
   }
   //Mutators
   void setXvertices(float *xVer) {
       *x = *xVer;
      
   }
   void setYvertices(float *yVer) {
       *y = *yVer;
   }
   //Accessors
   float* getXvertices() {
       return x;
   }
   float* getYvertices() {
       return y;
   }
   //Peimeter finding method
   double Perimeter() {
       double perimeter = 0;
       for (int i = 0; i < n; i++) {
           perimeter += sqrt(pow((*x+(i + 1) - *x+i), 2) + pow((*y + (i + 1) - *y + i), 2));
       }
       return perimeter;
   }
   //Area finding method
   double Area() {
       double area = 0;
       // Calculate value of shoelace formula
       int j = n - 1;
       for (int i = 0; i < n; i++)
       {
           area += (*x+j + *x+i) * (*y+j - *y+i);
           j = i; // j is previous vertex to i
       }

       // Return absolute value
       return abs(area / 2.0);
   }
};
//Child class
class triangle:public poly {
   //Member method
public:
   //Constructor
   triangle(int n) :poly(n) {
       n = 3;
   }
   //Area calculator
   double Area() {
       //double b= sqrt(pow((*x + 2 - *x + 1), 2) + pow((*y + 2 - *y + 1), 2)))
       double apothem= (sqrt(pow((*x + 3 - *x + 2), 2) + pow((*y + 3 - *y + 2), 2)));
       double area =( (Perimeter()*apothem)/2);
       // Calculate value of shoelace formula
      
       return area;
   }

};
//Child class
class quadilateral :public poly {
   //Member methods
public:
   //Constructor
   quadilateral(int n) :poly(n) {
       n = 4;
   }
   //Area calculation
   double Area() {
       //double b= sqrt(pow((*x + 2 - *x + 1), 2) + pow((*y + 2 - *y + 1), 2)))
       double apothem = (sqrt(pow((*x + 2 - *x + 1), 2) + pow((*y + 2 - *y + 1), 2)));
       double area = ((Perimeter()*apothem) / 2);
       // Calculate value of shoelace formula

       return area;
   }

};
//Driver method
int main()
{
   //Variables for choice and input and array
   char ch;
   int v;
   float *x, *y;
   cout << "      User menu :" << endl;
   //Prompt user for choice
   cout << "(P)olygon\n(T)riangle\n(Q)uadrilateral\n Enter your choice:";
   cin >> ch;
   //If polygon
   if (ch == 'p' || ch == 'P') {
       //Prompt for number of vertices
       cout << "Enter the number of vertices:";
       cin >> v;
       //Set array that size
       x = new float[v];
       y = new float[v];
       //Object creation
       poly p(v);
       //Values of vertices
       cout << "Enter x values:";
       for (int i = 0; i < v; i++) {
           cin >> x[i];
       }
       cout << "Enter y values:";
       for (int i = 0; i < v; i++) {
           cin >> y[i];
       }
       //Set vertices array
       p.setXvertices(x);
       p.setYvertices(y);
       //Display area and perimeter
       cout << "Perimeter of Polygon=" << setprecision(2) << p.Perimeter() << endl;
       cout << "Area of Polygon=" << setprecision(2) << p.Area() << endl;
   }
   //If triangle
   else if (ch == 't' || ch == 'T') {
       //set array size
       v = 3;
       x = new float[v];
       y = new float[v];
       //object creation
       triangle t(v);
       //values
       cout << "Enter x values:";
       for (int i = 0; i < v; i++) {
           cin >> x[i];
       }
       cout << "Enter y values:";
       for (int i = 0; i < v; i++) {
           cin >> y[i];
       }
       //set array
       t.setXvertices(x);
       t.setYvertices(y);
       //Display result
       cout << "Perimeter of Triangle=" << setprecision(2) << t.Perimeter() << endl;
       cout << "Area of Tringle=" << setprecision(2) << t.Area() << endl;
   }
   //If quadrilateral
   else if (ch == 'q' || ch == 'Q') {
       //Set array size
       v = 4;
       x = new float[v];
       y = new float[v];
       //Object creation
       quadilateral q(v);
       cout << "Enter x values:";
       for (int i = 0; i < v; i++) {
           cin >> x[i];
       }
       cout << "Enter y values:";
       for (int i = 0; i < v; i++) {
           cin >> y[i];
       }
       //set values in arrays
       q.setXvertices(x);
       q.setYvertices(y);
       //display result
       cout << "Perimeter of Quadrilateral=" << setprecision(2) << q.Perimeter() << endl;
       cout << "Area of Quadrilateral=" << setprecision(2) << q.Area() << endl;
   }
   //Wrong choice
   else {
       cout << "Wrong choice" << endl;
   }
    return 0;
}

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Output

      User menu :
(P)olygon
(T)riangle
(Q)uadrilateral
Enter your choice:q
Enter x values:1
2
3
4
Enter y values:5
6
7
8
Perimeter of Quadrilateral=23
Area of Quadrilateral=48
Press any key to continue . . .