Triangle - scanline filling

Hi guys
I've come to a halt, i can't seem to figure out an efficient method of implementing a triangle scan line algorithm or even a messy one that works. So far my function can take 3 points and obtain coordinates needed to connect the points, these coordinates are used for my triangle's edges. Now to use these edges in the scan line algorithm i need to figure out which edge coordinates belong on the left and right. I've managed to get a flat base triangle filled but any other triangle cases just have me stumped for logic :-(

One idea i had was to concatenate the edge lists of 2 smaller sides of a triangle and somehow find which side it belongs to.

Code:

void Core::drawTriangle(Point a, Point b, Point c)
{
	vector<Point> AB;
	vector<Point> AC;
	vector<Point> BC;

	vector<Point> lEdge;
	vector<Point> rEdge;

	makeLine(a, b, &AB);
	makeLine(a, c, &AC);
	makeLine(b, c, &BC);

        //this works for an equilateral triangle
        int i = 0;
        for (int y = a.y; y < b.y; y++)
	{
		for (int x = AC[i].x; x < AB[i].x; x++)
		{
			putpixel(x, y, 0, 200, 0, 0);
		}
		i++;
	}
}

Did you try this?
triangle scanline fill - Google Search