#include <graphics.h>
#include <iostream>
using namespace std;
int main()
{
    int n, i, j, k, gd, gm, dy, dx;
    int x, y, temp;
    int a[20][2], xi[20];
    float slope[20];
    int temp1 = 0;
    cout << "\nEnter the number of edges ";
    cin >> n;
    for (i = 0; i < n; i++)
    {
        cout << "Enter the coordinate x" << i + 1 << " ";
        cin >> a[i][0];
        cout << "Enter the coordinate y" << i + 1 << " ";
        cin >> a[i][1];
    }
    a[n][0] = a[0][0];
    a[n][1] = a[0][1];
    initgraph(&gd, &gm, NULL);
    setcolor(YELLOW);
    for (i = 0; i < n; i++)
    {
        line(a[i][0], a[i][1], a[i + 1][0], a[i + 1][1]);
    }
    for (i = 0; i < n; i++)
    {
        dy = a[i + 1][1] - a[i][1];
        dx = a[i + 1][0] - a[i][0];
        if (dy == 0)
            slope[i] = 1.0;
        if (dx == 0)
            slope[i] = 0.0;
        if ((dy != 0) && (dx != 0))
        {
            slope[i] = (float)dx / dy;
        }
    }
    for (y = 0; y < 400; y++)
    {
        k = 0;
        for (i = 0; i < n; i++)
        {
            if (((a[i][1] <= y) && (a[i + 1][1] > y)) || ((a[i][1] > y) && (a[i + 1][1] <= y)))
            {
                xi[k] = (int)(a[i][0] + slope[i] * (y - a[i][1]));
                k++;
            }
        }
        for (j = 0; j < k; j++)
            for (i = 0; i < k; i++)
            {
                if (xi[i] > xi[i + 1])
                {
                    temp = xi[i];
                    xi[i] = xi[i + 1];
                    xi[i + 1] = temp;
                }
            }
        setcolor(YELLOW);
        for (i = 0; i < k; i += 2)
        {
            line(xi[i], y, xi[i + 1] + 1, y);
            temp1 = i;
        }
    }
    delay(7000);
    return 0;
}

kodingwindow@kw:~$ g++ kw.cpp -lgraph
kodingwindow@kw:~$ ./a.out
Enter the number of edges 6
Enter the coordinate x1 100
Enter the coordinate y1 100
Enter the coordinate x2 150
Enter the coordinate y2 150
Enter the coordinate x3 150
Enter the coordinate y3 200
Enter the coordinate x4 100
Enter the coordinate y4 250
Enter the coordinate x5 50
Enter the coordinate y5 200
Enter the coordinate x6 50
Enter the coordinate y6 150