#include <graphics.h>
#include <iostream>
using namespace std;
int main()
{
    int gd = 0, gm = 9, x1, y1, x2, y2;
    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);
    line(x1, y1, x2, y2);
    delay(2000);
    return 0;
}

codeaft@codeaft:~$ g++ codeaft.cpp -lgraph
codeaft@codeaft:~$ ./a.out
Enter the x1 coordinate 50
Enter the y1 coordinate 50
Enter the x2 coordinate 150
Enter the y2 coordinate 150