如何在Java中制作星号的左箭头？

Question

I'am working on a program that makes right and left arrows. They are extended from a ShapeBase class which is implemented from a ShapeInterface. I didn't paste them so it wouldn't look overwhelming. The problem is I have figured out the right arrow ( I believe) but cannot find my way to getting the left arrow. I keep getting confused and cant seem to understand how to do it. Any help is appreciated. RightArrow Example Output

public abstract class ShapeBase implements ShapeInterface
{
private int offset;

public ShapeBase( )
{
    offset = 0;
}

public ShapeBase(int theOffset)
{
    offset = theOffset;
}

public abstract void drawHere( );

public void drawAt(int lineNumber)
{
    for (int count = 0; count < lineNumber; count++)
        System.out.println( );
    drawHere( );
}

public void setOffset(int newOffset)
{
    offset = newOffset;
}

public int getOffset( )
{
    return offset;
}
}





public class RightArrow extends ShapeBase
{
private int tail;
private int width;

public RightArrow()
{
    super();
    tail = 0;
    width = 0;
}

public RightArrow(int theOffset ,int tailSize, int theWidth)
{
    super(theOffset);
    tail = tailSize;
    width = theWidth;
    set(tail , width);
}
public void set(int newHeight, int newWidth)
{
    tail = newHeight;
    width = newWidth;
}

public void drawHere()
{
    topArrowhead();
    ArrowTail();
    bottomArrowHead();
}
public void topArrowhead()
{
    skipSpaces(getOffset());
    System.out.println("*");

    for(int i = 0; i<width/2; i++)
    {
        skipSpaces(getOffset());
        System.out.print("*");
        skipSpaces(i);
        System.out.println("*");
    }
}

// method to draw the arrow tail
public void ArrowTail()
{
    for(int count=0; count<tail; count++)
    {
        System.out.print("*");
    }
    skipSpaces(tail+width);
    System.out.print("*");

}

// method to draw bottom of arrowhead
public void bottomArrowHead()
{
    for(int i =1;i<width/2; i--)
    {
        skipSpaces(getOffset());
        System.out.print("*");
        skipSpaces(i);
        System.out.println("*");
    }
    skipSpaces(getOffset());
    System.out.println("*");
}

private static void skipSpaces(int number)
{
    for (int count=0; count< number; count++)
    System.out.print(" ");
}
}

FOR THE LEFT ARROW CLASS, I believe these are the only methods need changing. I just don't know how

    public void topArrowhead()
        {
            skipsSpaces(getOffset());
            System.out.println("*");

            for(int i = 0 i<width/2; i++)
            {
                skipSpaces(getOffset());
                System.out.print("*");
                skipSpaces(i);
                System.out.println("*");
            }
        }

        // method to draw the arrow tail
        public void ArrowTail()
        {

        }

        // method to draw bottom of arrowhead
        public void bottomArrowHead()
        {

        }

        private static void skipSpaces(int number)
        {
            for (int count=0; count< number; count--)
            System.out.print(" ");
        }
}

Answer 1

This is how you can draw a left arrow,it doesn't uses your methods(as you not provided source for ShapeBase ) but you can see the implementation below how its get created and then can use in your own way.

public class LeftArrow
{
    private int tail=15;
    private int width=7;

    //Method to draw the left arrow    
    public void DrawArrow()
    {
        for(int i = 0,r=0; i<width; i++)
        {
            //for spaces before head
            for(int j=0;j<(width/2)-r;j++)
                    System.out.print(" ");

            for(int j=0;j<=r;j++)
            {
                if(j==r || j==0)
                System.out.print("*");
                else
                System.out.print(" ");//for spaces inside head
            }
            if(i==width/2)//to draw tail after the mid of head
                ArrowTail();

            if(i<width/2)//controls the increment & decrements of spaces before head
                r++;
            else r--;

            System.out.println();
        }
    }

    // method to draw the arrow tail
    public void ArrowTail()
    {
        for(int count=0; count<tail; count++)
        {
            System.out.print("*");
        }
    }

    public static void main(String[] args)
    {
        LeftArrow Arrow = new LeftArrow();
        Arrow.DrawArrow();
    }
}