#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <time.h>
#include <string.h>
#include "graphics.h"

#define ESC 0x1b

void main () {

srand(time(NULL));

int GraphDriver=0; GraphMode=0;

initgraph (&GraphDriver ,&GraphMode, "", 640,480);

char tempstring[80];

getch() ;

}

}

There is a C++ code snippet right here on DaniWeb called "Add a little Graphics to your Console" at:
http://www.daniweb.com/code/snippet173.html

You could potentially draw short lines following the x,y coordinates of your sin(x) function.

Forget about the old graphics.h and Borland BGI DOS stuff, that was left in the 16 bit graveyard a long time ago!

#include "stdafx.h"
#include <graphics.h>
#include <conio.h>

void main()
{
int gd=DETECT, gm;
initgraph(&gd,&gm,"");

int x,y, j=250 ;

setbkcolor(WHITE);
setcolor(LIGHTBLUE);

outtextxy(3,5," I am so stupid hyong I am so stupid sorry sorry !!! "); // output "line" text

x = getmaxx();
y = getmaxy();

x=j;

line(j,0,x,y);

x = getmaxx();
y = getmaxy();

y=j;

line(0,j,x,y);
/*void line(int x0, int y0, int x1, int y1)

{
POINT line[2];
line[0].x = x0;
line[0].y = y0;
line[1].x = x1;
line[1].y = y1;
drawpoly(2, (int*)&line);
}
*/

getch();

closegraph(); // escape graphic mode
}
Thanks very much ....