form1.cs

用图像表示链表的创建、插入和删除

                            a.current = b;

                        x = x - width - 10;
                        if (b.next != null)
                            b = b.next;
                        else
                            break;
                    }
                }
                    y += height + 10;
            }

            Draw();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "")
            {
                MessageBox.Show("请输入初始化单链表长度", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Draw();
            }
            else
            {
                int length = Convert.ToInt16(textBox1.Text);

                if (length > 99)
                {
                    MessageBox.Show(" 初始化单链表长度应在0~99之间", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    Draw();
                    return;
                }

                if (radioButton1.Checked)
                {
                    SListnode b = new SListnode(1);
                    a.head.next = b;
                    a.current = b;

                    for (int i = 2; i < length + 1; i++)
                    {
                        b = new SListnode(i);
                        a.current.next = b;
                        a.current = b;
                    }

                    Draw();
                }

                if (radioButton2.Checked)
                {
                    SListnode b = new SListnode(length);
                    a.head.next = b;
                    a.current = b;

                    for (int i = length-1; i >0; i--)
                    {
                        b = new SListnode(i);
                        a.current.next = b;
                        a.current = b;
                    }

                    a.current = a.head.next;

                    Draw();
                }
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            
            if (textBox1.Text == "")
            {
                MessageBox.Show("请先进行初始化", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Draw();
            }
            else
            {
                int length = Convert.ToInt16(textBox1.Text);

                if (length > 99)
                {
                    MessageBox.Show(" 初始化单链表长度应在0~99之间", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    Draw();
                    return;
                }

                if (radioButton2.Checked)
                {
                    SListnode b = new SListnode(1);
                    a.head.next = b;
                    a.current = b;

                    for (int i = 2; i < length + 1; i++)
                    {
                        b = new SListnode(i);
                        a.current.next = b;
                        a.current = b;
                    }

                    Draw();
                }

                if (radioButton1  .Checked)
                {
                    SListnode b = new SListnode(length);
                    a.head.next = b;
                    a.current = b;

                    for (int i = length - 1; i > 0; i--)
                    {
                        b = new SListnode(i);
                        a.current.next = b;
                        a.current = b;
                    }

                    a.current = a.head.next;

                    Draw();
                }
            }
        }

        private void button5_Click(object sender, EventArgs e)
        {
            a.MakeEmpty();
            Draw();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            a.current = a.head;
            Draw();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            if (a.current.next != null)
            {
                a.current = a.current.next;
                Draw();
            }
            else
            {
                MessageBox.Show("已经到达单链表尾端", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Draw();
            }
        }


     


        private void button9_Click(object sender, EventArgs e)
        {
            if (a.current != null )
            {
                textBox3.Text = a.current.ToString();
                textBox4.Text = Convert.ToString(a.current.data);
                if(a.current.next!=null)
                    textBox5.Text = a.current.next.data.ToString();
                
            }
            else
            {
                MessageBox.Show("请初始化单链表", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Draw();
            }

        }


        private void button7_Click_1(object sender, EventArgs e)
        {
            if (a.Length() == 99)
            {
                MessageBox.Show("单链表长度应在0~99之间", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            bool before;
            if (textBox2.Text == "")
            {
                MessageBox.Show("请在文本框中输入插入值", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Draw();
            }
            else
            {
                int newdata = Convert.ToInt16(textBox2.Text);
                if (radioButton3.Checked)
                {
                    before = true;
                    a.insert(newdata, before);
                    Draw();
                }

                if (radioButton4.Checked)
                {
                    before = false;
                    a.insert(newdata , before);
                    Draw();
                }
            }
        }

        private void button6_Click(object sender, EventArgs e)
        {
            if (textBox2.Text == "")
            {
                MessageBox.Show("请输入修改值", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Draw();
            }
            else
            {
                if (a.current  ==null )
                {
                    MessageBox.Show("请初始化单链表", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    Draw();
                }
                else
                {
                    int newdata = Convert.ToInt16(textBox2.Text);
                    a.modifydata(newdata);
                    Draw();
                }
            }
        }

        
        private void button8_Click_1(object sender, EventArgs e)
        {
            if (a.current == a.head)
            {
                MessageBox.Show("删除错误，不能删除头结点", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Draw();
            }
            else
            {
                a.delete();
                Draw();
            }

        }

        private void button10_Click(object sender, EventArgs e)
        {
            Application.Exit();

        }

   
    }
}