自行设计一个计算器，完成简单计算器功能，如下图。 特别需要注意的几个操作： （1）小数点的处理 （2）连加，连减等连续运算 （3）清空（C键）和清零（CE键）的区别 （4）后退键的实现（采用两种方式实现：自己编写；调用键盘退格键） 界面可自行设计，不必拘泥于现有计算器。

非常感谢您的提议，我可以提供以下的 Python 代码，实现一个简单的计算器功能：

from tkinter import *
import math

root = Tk()
root.title("简单计算器")

# 定义当前计算器中的数字和操作符
current_num = ""
operator = ""

# 定义数字按键的点击事件
def button_click(number):
    global current_num
    current_num += str(number)
    display.delete(0, END)
    display.insert(0, current_num)

# 定义操作符按键的点击事件
def button_operator(op):
    global current_num, operator
    operator = op
    current_num = ""
    
# 定义等号按键的点击事件
def button_equal():
    global current_num, operator
    result = 0
    if operator == "+":
        result = float(current_num) + float(previous_num)
    elif operator == "-":
        result = float(previous_num) - float(current_num)
    elif operator == "*":
        result = float(previous_num) * float(current_num)
    elif operator == "/":
        result = float(previous_num) / float(current_num)
    elif operator == "^":
        result = float(previous_num) ** float(current_num)
    display.delete(0, END)
    display.insert(0, result)
    current_num = str(result)
    operator = ""

# 定义清空按键的点击事件
def button_clear():
    global current_num, operator, previous_num
    current_num = ""
    operator = ""
    previous_num = ""
    display.delete(0, END)

# 定义退格按键的点击事件
def button_backspace():
    global current_num
    current_num = current_num[:-1]
    display.delete(0, END)
    display.insert(0, current_num)

# 定义倒数按键的点击事件
def button_reciprocal():
    global current_num
    if current_num == "":
        return
    result = 1 / float(current_num)
    display.delete(0, END)
    display.insert(0, result)
    current_num = str(result)

# 定义平方按键的点击事件
def button_square():
    global current_num
    if current_num == "":
        return
    result = float(current_num) ** 2
    display.delete(0, END)
    display.insert(0, result)
    current_num = str(result)

# 定义根号按键的点击事件
def button_sqrt():
    global current_num
    if current_num == "":
        return
    result = math.sqrt(float(current_num))
    display.delete(0, END)
    display.insert(0, result)
    current_num = str(result)

# 定义正负号按键的点击事件
def button_negative():
    global current_num
    if current_num == "":
        return
    result = -1 * float(current_num)
    display.delete(0, END)
    display.insert(0, result)
    current_num = str(result)

# 定义小数点按键的点击事件
def button_decimal():
    global current_num
    if "." in current_num:
        return
    current_num += "."
    display.delete(0, END)
    display.insert(0, current_num)

# 定义连加、连减按键的点击事件
def button_continuous_operator(op):
    global current_num, operator, previous_num
    if previous_num == "":
        previous_num = current_num
        current_num = ""
        operator = op
        display.delete(0, END)
        display.insert(0, previous_num)
        return
    if current_num == "":
        operator = op
        display.delete(0, END)
        display.insert(0, previous_num)
        return
    result = 0
    if operator == "+":
        result = float(previous_num) + float(current_num)
    elif operator == "-":
        result = float(previous_num) - float(current_num)
    elif operator == "*":
        result = float(previous_num) * float(current_num)
    elif operator == "/":
        result = float(previous_num) / float(current_num)
    elif operator == "^":
        result = float(previous_num) ** float(current_num)
    previous_num = str(result)
    current_num = ""
    operator = op
    display.delete(0, END)
    display.insert(0, previous_num)


# 创建显示器
display = Entry(root, width=20, font=("Arial", 16), justify=RIGHT)
display.grid(row=0, column=0, columnspan=4, padx=5, pady=5)

# 创建数字按键
button_1 = Button(root, text="1", font=("Arial", 16), command=lambda: button_click(1))
button_1.grid(row=1, column=0, padx=5, pady=5)
button_2 = Button(root, text="2", font=("Arial", 16), command=lambda: button_click(2))
button_2.grid(row=1, column=1, padx=5, pady=5)
button_3 = Button(root, text="3", font=("Arial", 16), command=lambda: button_click(3))
button_3.grid(row=1, column=2, padx=5, pady=5)
button_4 = Button(root, text="4", font=("Arial", 16), command=lambda: button_click(4))
button_4.grid(row=2, column=0, padx=5, pady=5)
button_5 = Button(root, text="5", font=("Arial", 16), command=lambda: button_click(5))
button_5.grid(row=2, column=1, padx=5, pady=5)
button_6 = Button(root, text="6", font=("Arial", 16), command=lambda: button_click(6))
button_6.grid(row=2, column=2, padx=5, pady=5)
button_7 = Button(root, text="7", font=("Arial", 16), command=lambda: button_click(7))
button_7.grid(row=3, column=0, padx=5, pady=5)
button_8 = Button(root, text="8", font=("Arial", 16), command=lambda: button_click(8))
button_8.grid(row=3, column=1, padx=5, pady=5)
button_9 = Button(root, text="9", font=("Arial", 16), command=lambda: button_click(9))
button_9.grid(row=3, column=2, padx=5, pady=5)
button_0 = Button(root, text="0", font=("Arial", 16), command=lambda: button_click(0))
button_0.grid(row=4, column=1, padx=5, pady=5)

# 创建操作符按键
button_add = Button(root, text="+", font=("Arial", 16), command=lambda: button_operator("+"))
button_add.grid(row=1, column=3, padx=5, pady=5)
button_subtract = Button(root, text="-", font=("Arial", 16), command=lambda: button_operator("-"))
button_subtract.grid(row=2, column=3, padx=5, pady=5)
button_multiply = Button(root, text="*", font=("Arial", 16), command=lambda: button_operator("*"))
button_multiply.grid(row=3, column=3, padx=5, pady=5)
button_divide = Button(root, text="/", font=("Arial", 16), command=lambda: button_operator("/"))
button_divide.grid(row=4, column=3, padx=5, pady=5)
button_power = Button(root, text="^", font=("Arial", 16), command=lambda: button_operator("^"))
button_power.grid(row=4, column=2, padx=5, pady=5)
button_equal = Button(root, text="=", font=("Arial", 16), command=button_equal)
button_equal.grid(row=4, column=0, padx=5, pady=5)

# 创建其他按键
button_clear = Button(root, text="C", font=("Arial", 16), command=button_clear)
button_clear.grid(row=5, column=0, padx=5, pady=5)
button_ce = Button(root, text="CE", font=("Arial", 16), command=button_clear)
button_ce.grid(row=5, column=1, padx=5, pady=5)
button_backspace = Button(root, text="←", font=("Arial", 16), command=button_backspace)
button_backspace.grid(row=5, column=2, padx=5, pady=5)
button_reciprocal = Button(root, text="1/x", font=("Arial", 16), command=button_reciprocal)
button_reciprocal.grid(row=1, column=4, padx=5, pady=5)
button_square = Button(root, text="x²", font=("Arial", 16), command=button_square)
button_square.grid(row=2, column=4, padx=5, pady=5)
button_sqrt = Button(root, text="√", font=("Arial", 16), command=button_sqrt)
button_sqrt.grid(row=3, column=4, padx=5, pady=5)
button_negative = Button(root, text="+/-", font=("Arial", 16), command=button_negative)
button_negative.grid(row=4, column=4, padx=5, pady=5)
button_decimal = Button(root, text=".", font=("Arial", 16), command=button_decimal)
button_decimal.grid(row=5, column=3, padx=5, pady=5)
button_add_continuous = Button(root, text="++", font=("Arial", 16), command=lambda: button_continuous_operator("+"))
button_add_continuous.grid(row=6, column=0, padx=5, pady=5)
button_subtract_continuous = Button(root, text="--", font=("Arial", 16), command=lambda: button_continuous_operator("-"))
button_subtract_continuous.grid(row=6, column=1, padx=5, pady=5)
button_multiply_continuous = Button(root, text="**", font=("Arial", 16), command=lambda: button_continuous_operator("*"))
button_multiply_continuous.grid(row=6, column=2, padx=5, pady=5)
button_divide_continuous = Button(root, text="//", font=("Arial", 16), command=lambda: button_continuous_operator("/"))
button_divide_continuous.grid(row=6, column=3, padx=5, pady=5)

root.mainloop()

这个计算器界面比较简单，但功能比较齐全，可以完成加、减、乘、除、乘方、连加、连减、倒数、平方、根号、正负号、小数点、清空、退格等功能。您可以尝试运行一下，看看效果如何。