Polygon Clipping, won't clip

Hello, I am stuck on this Polygon Clipping Assignment. It won't clip.
http://www.megafileupload.com/en/file/383064/cg1-clip-zip.html

This is what I have so far:

//
//  Clipper.java
//  
//

/**
 * Object for performing clipping
 *
 */

public class clipper {
    
    /**
     * clipPolygon
     * 
     * Clip the polygon with vertex count in and vertices inx/iny
     * against the rectangular clipping region specified by lower-left corner
     * (x0,y0) and upper-right corner (x1,y1). The resulting vertices are
     * placed in outx/outy.  
     * 
     * The routine should return the with the vertex count of polygon
     * resultinhg from the clipping.
     *
     * @param in the number of vertices in the polygon to be clipped
     * @param inx - x coords of vertices of polygon to be clipped.
     * @param int - y coords of vertices of polygon to be clipped.
     * @param outx - x coords of vertices of polygon resulting after clipping.
     * @param outy - y coords of vertices of polygon resulting after clipping.
     * @param x0 - x coord of lower left of clipping rectangle.
     * @param y0 - y coord of lower left of clipping rectangle.
     * @param x1 - x coord of upper right of clipping rectangle.
     * @param y1 - y coord of upper right of clipping rectangle.
     *
     * @return number of vertices in the polygon resulting after clipping
     * 
     */
	public float intersectX;
	public float intersectY;
	public float clipXmin;
	public float clipYmin;
	public float clipYmax;
	public float clipXmax;
	public int clipBorder;
	
    public int clipPolygon(int in, float inx[], float iny[], float outx[],
                float outy[],  float x0, float y0, float x1, float y1)
    {
        int numberOfVerticies = 0;
        int n;
        
        float Lx,Ly,Cx,Cy;
      
        Lx = inx[in-1];
        Ly = iny[in-1];
        
        for (n = 0; n < in; n++){
			Cx = inx[n];
			Cy = iny[n];
			
			
			
		if(isInside(Cx, Cy, clipBorder)){
			if(isInside(Lx,Ly,clipBorder)){
				outx[numberOfVerticies] = Cx;
				outy[numberOfVerticies] = Cy;
				numberOfVerticies++;
				
				
			}
			else{
				isIntersect(Lx,Ly,Cx,Cy,clipBorder);
				outx[numberOfVerticies] = intersectX;
				outy[numberOfVerticies] = intersectY;
				numberOfVerticies++;
				outx[numberOfVerticies] = Cx;
				outy[numberOfVerticies] = Cy;
				numberOfVerticies++;
				
				
			}
		}
		else{
				if(isInside(Lx,Ly,clipBorder)){
					isIntersect(Lx,Ly,Cx,Cy,clipBorder);
					outx[numberOfVerticies] = intersectX;
					outy[numberOfVerticies] = intersectY;
					numberOfVerticies++;
					
					}
				}
			Lx = Cx;
			Ly = Cy;
			
			
			}
        return numberOfVerticies; // should return number of verricies in clipped poly.
    }
   


public boolean isInside(float newX, float newY, int clipBorder){
	if(clipBorder == 0 && newY > clipYmin){
		return true;
	}
	else if(clipBorder == 1 && newX > clipXmin){
		return true;
	}
	else if(clipBorder == 2 && newY < clipYmax){
		return true;
	}
	else if (clipBorder == 3 && newX < clipXmax){
		return true;
	}
	return false;
}
public void isIntersect(float x0, float x1, float y0, float y1, int clipBorder){
	float xDifference = x1 -x0;
	float yDifference = y1 - y0;
	
	if(xDifference == 0 || yDifference == 0){
		
		if(clipBorder == 0){
			intersectX = x0;
			intersectY = clipYmin;
		}
		else if(clipBorder == 1){
			intersectX = clipXmin;
			intersectY = y0;
		}
		else if(clipBorder == 2){
			intersectX = x0;
			intersectY = clipYmax;
		}
		else if(clipBorder == 3){
			intersectX = clipXmax;
			intersectY = y0;
		}
		return;
	}
	if(clipBorder == 0){
		
		//intersectX = x0 + ((((((int)xDifference) * ((int)clipYmin - (int)y0))<<8) / ((int)yDifference))>>8);
		intersectX = x0 + ((clipYmax - y0)/(y1-y0/x1-x0));
		intersectY = clipYmin;
	}
	else if(clipBorder == 1){
		intersectX = clipXmin;
		intersectY = (y1-y0/x1-x0)*(clipXmax-x0) + y0;
		//intersectY = y0 + ((((((int)yDifference) * ((int)clipXmin - (int)x0))<<8) / ((int)xDifference))>>8);  
	}
	else if(clipBorder == 2){
		//intersectX = x0 + ((((((int)xDifference) * ((int)clipYmax - (int)y0))<<8) / ((int)yDifference))>>8);
		intersectX = x0+((clipYmin-y0)/(y1-y0/x1-x0));
		intersectY = clipYmax;
	}
	else if(clipBorder == 3){
		intersectX = clipXmax;
		//intersectY = y0 + ((((((int)yDifference) * ((int)clipXmax - (int)x0))<<8) / ((int)xDifference))>>8);  
		intersectY = (y1-y0/x1-x0)*(clipXmax-x0) + y0;
	}
}

}

The rest of the package that is needed to run it.

The results should be like this.
http://i.imgur.com/aDVx4.jpg