typedef int OutCode;
 
const int INSIDE = 0; // 0000
const int LEFT = 1;   // 0001
const int RIGHT = 2;  // 0010
const int BOTTOM = 4; // 0100
const int TOP = 8;    // 1000
 
// Compute the bit code for a point (x, y) using the clip rectangle
// bounded diagonally by (xmin, ymin), and (xmax, ymax)
 
// ASSUME THAT xmax , xmin , ymax and ymin are global constants.
 
OutCode ComputeOutCode(double x, double y)
{
        OutCode code;
 
        code = INSIDE;          // initialised as being inside of clip window
 
        if (x < xmin)           // to the left of clip window
                code |= LEFT;
        else if (x > xmax)      // to the right of clip window
                code |= RIGHT;
        if (y < ymin)           // below the clip window
                code |= BOTTOM;
        else if (y > ymax)      // above the clip window
                code |= TOP;
 
        return code;
}
 
// Cohen–Sutherland clipping algorithm clips a line from
// P0 = (x0, y0) to P1 = (x1, y1) against a rectangle with 
// diagonal from (xmin, ymin) to (xmax, ymax).
void CohenSutherlandLineClipAndDraw(double x0, double y0, double x1, double y1)
{
        // compute outcodes for P0, P1, and whatever point lies outside the clip rectangle
        OutCode outcode0 = ComputeOutCode(x0, y0);
        OutCode outcode1 = ComputeOutCode(x1, y1);
        bool accept = false;
 
        while (true) {
                if (!(outcode0 | outcode1)) { // Bitwise OR is 0. Trivially accept and get out of loop
                        accept = true;
                        break;
                } else if (outcode0 & outcode1) { // Bitwise AND is not 0. Trivially reject and get out of loop
                        break;
                } else {
                        // failed both tests, so calculate the line segment to clip
                        // from an outside point to an intersection with clip edge
                        double x, y;
 
                        // At least one endpoint is outside the clip rectangle; pick it.
                        OutCode outcodeOut = outcode0? outcode0 : outcode1;
 
                        // Now find the intersection point;
                        // use formulas y = y0 + slope * (x - x0), x = x0 + (1 / slope) * (y - y0)
                        if (outcodeOut & TOP) {           // point is above the clip rectangle
                                x = x0 + (x1 - x0) * (ymax - y0) / (y1 - y0);
                                y = ymax;
                        } else if (outcodeOut & BOTTOM) { // point is below the clip rectangle
                                x = x0 + (x1 - x0) * (ymin - y0) / (y1 - y0);
                                y = ymin;
                        } else if (outcodeOut & RIGHT) {  // point is to the right of clip rectangle
                                y = y0 + (y1 - y0) * (xmax - x0) / (x1 - x0);
                                x = xmax;
                        } else if (outcodeOut & LEFT) {   // point is to the left of clip rectangle
                                y = y0 + (y1 - y0) * (xmin - x0) / (x1 - x0);
                                x = xmin;
                        }
 
                        //NOTE:*****************************************************************************************
 
                        /* if you follow this algorithm exactly(at least for c#), then you will fall into an infinite loop 
                        in case a line crosses more than two segments. to avoid that problem, leave out the last else
                        if(outcodeOut & LEFT) and just make it else*/
 
                        //**********************************************************************************************
 
                        // Now we move outside point to intersection point to clip
                        // and get ready for next pass.
                        if (outcodeOut == outcode0) {
                                x0 = x;
                                y0 = y;
                                outcode0 = ComputeOutCode(x0, y0);
                        } else {
                                x1 = x;
                                y1 = y;
                                outcode1 = ComputeOutCode(x1, y1);
                        }
                }
        }
        if (accept) {
               // Following functions are left for implementation by user based on his platform(OpenGL/graphics.h etc.)
               DrawRectangle(xmin, ymin, xmax, ymax);
               LineSegment(x0, y0, x1, y1);
        }
}