line function in c programming :-
Well line function in c computer graphics is used as it name says to draw a line from a point(x1,y1) to point(x2,y2) where (x2,y2) are end points to draw a line.
Here you can also check the c program to draw a line in computer graphics.
C example program
#include <graphics.h>
#include <conio.h>
main()
{
int gd = DETECT, gm;
initgraph(&gd, &gm, "C:\\TC\\BGI");
line(100, 100, 200, 200);
getch();
closegraph();
return 0;
}