#include <graphics.h>
#include <iostream>
using namespace std;
class polygon
{
private:
    int x1, y1, x2, y2, x, y, k;
    float dx, dy, step, xinc, yinc;

public:
    void SRtri(int x1, int y1, int x2, int y2)
    {
        dx = x2 - x1;
        dy = y2 - y1;
        if (abs(dx) >= abs(dy))
        {
            step = abs(dx);
        }
        else
        {
            step = abs(dy);
        }
        xinc = dx / step;
        yinc = dy / step;
        x = x1;
        y = y1;
        putpixel(x, y, WHITE);
        for (k = 0; k < step; k++)
        {
            x = x + xinc;
            y = y + yinc;
            putpixel(x, y, WHITE);
        }
    }
};

int main()
{
    int x1, x2, y1, y2, ch, x3, y3;
    int gd = DETECT, gm;
    polygon p;
    do
    {
        cout << "———————————————————————————————————————————";
        cout << "\nProgram to draw the convex polygons";
        cout << "\n———————————————————————————————————————————";
        cout << "\n1.Square\n2.Rectangle\n3.Triangle\n4.Exit";
        cout << "\n———————————————————————————————————————————";
        cout << "\nEnter your choice ";
        cin >> ch;
        switch (ch)
        {
        case 1:
            cout << "Enter the x1 coordinate ";
            cin >> x1;
            cout << "Enter the y1 coordinate ";
            cin >> y1;
            cout << "Enter the x2 coordinate ";
            cin >> x2;
            cout << "Enter the y2 coordinate ";
            cin >> y2;
            initgraph(&gd, &gm, NULL);
            p.SRtri(x1, y1, x1, y2);
            p.SRtri(x1, y1, x2, y1);
            p.SRtri(x1, y2, x2, y2);
            p.SRtri(x2, y1, x2, y2);
            delay(3000);
            closegraph();
            break;
        case 2:
            cout << "Enter the x1 coordinate ";
            cin >> x1;
            cout << "Enter the y1 coordinate ";
            cin >> y1;
            cout << "Enter the x2 coordinate ";
            cin >> x2;
            cout << "Enter the y2 coordinate ";
            cin >> y2;
            initgraph(&gd, &gm, NULL);
            p.SRtri(x1, y1, x1, y2);
            p.SRtri(x1, y1, x2, y1);
            p.SRtri(x1, y2, x2, y2);
            p.SRtri(x2, y1, x2, y2);
            delay(3000);
            closegraph();
            break;
        case 3:
            cout << "Enter the x1 coordinate ";
            cin >> x1;
            cout << "Enter the y1 coordinate ";
            cin >> y1;
            cout << "Enter the x2 coordinate ";
            cin >> x2;
            cout << "Enter the y2 coordinate ";
            cin >> y2;
            cout << "Enter the x3 coordinate ";
            cin >> x3;
            cout << "Enter the y3 coordinate ";
            cin >> y3;
            initgraph(&gd, &gm, NULL);
            p.SRtri(x1, y1, x2, y2);
            p.SRtri(x2, y2, x3, y3);
            p.SRtri(x3, y3, x1, y1);
            delay(3000);
            closegraph();
            break;
        case 4:
            exit(0);
        default:
            cout << "\nWrong Choice Entered...Please Try Again\n";
        }
    } while (ch != 4);
    return 0;
}

kodingwindow@kw:~$ g++ kw.cpp -lgraph
kodingwindow@kw:~$ ./a.out
———————————————————————————————————————————
Program to draw the convex polygons
———————————————————————————————————————————
1.Square
2.Rectangle
3.Triangle
4.Exit
———————————————————————————————————————————
Enter your choice 1   
Enter the x1 coordinate 30
Enter the y1 coordinate 30
Enter the x2 coordinate 150
Enter the y2 coordinate 150

———————————————————————————————————————————
Program to draw the convex polygons
———————————————————————————————————————————
1.Square
2.Rectangle
3.Triangle
4.Exit
———————————————————————————————————————————
Enter your choice 2
Enter the x1 coordinate 30
Enter the y1 coordinate 30
Enter the x2 coordinate 150
Enter the y2 coordinate 100

———————————————————————————————————————————
Program to draw the convex polygons
———————————————————————————————————————————
1.Square
2.Rectangle
3.Triangle
4.Exit
———————————————————————————————————————————
Enter your choice 3
Enter the x1 coordinate 100
Enter the y1 coordinate 20
Enter the x2 coordinate 20
Enter the y2 coordinate 100
Enter the x3 coordinate 180
Enter the y3 coordinate 100