python 图形界面设计计算器实现 回退 和清空 。以及带有退出功能的菜单

好的，针对你的问题，我可以给出一份简单的Python代码实现，如下：

import tkinter as tk

class Calculator:
    def __init__(self, master):
        self.master = master
        master.title("Calculator")

        self.equation = tk.StringVar()
        self.equation.set("")

        # 创建显示计算结果的文本框
        self.result_display = tk.Entry(master, textvariable=self.equation, width=30, justify="right")
        self.result_display.grid(row=0, column=0, columnspan=4, padx=5, pady=5)

        # 创建清空和回退按钮
        self.clear_button = tk.Button(master, text="C", width=5, command=self.clear)
        self.clear_button.grid(row=1, column=0, padx=5, pady=5)
        self.back_button = tk.Button(master, text="<-", width=5, command=self.backspace)
        self.back_button.grid(row=1, column=1, padx=5, pady=5)

        # 创建数字和运算符按钮
        self.buttons = [
            "7", "8", "9", "/",
            "4", "5", "6", "*",
            "1", "2", "3", "-",
            "0", ".", "+", "="
        ]
        self.create_buttons()

        # 创建菜单
        menu = tk.Menu(master)
        master.config(menu=menu)
        file_menu = tk.Menu(menu)
        menu.add_cascade(label="File", menu=file_menu)
        file_menu.add_command(label="Exit", command=master.quit)

    def create_buttons(self):
        row = 2
        col = 0
        for button in self.buttons:
            command = lambda x=button: self.handle_click(x)
            if button == "0":
                tk.Button(self.master, text=button, width=11, command=command).grid(row=row, column=col, columnspan=2, padx=5, pady=5)
                col += 2
            elif button == "=":
                tk.Button(self.master, text=button, width=11, command=command).grid(row=row, column=col, columnspan=2, padx=5, pady=5)
                row += 1
                col = 0
            else:
                tk.Button(self.master, text=button, width=5, command=command).grid(row=row, column=col, padx=5, pady=5)
                col += 1

    def handle_click(self, button):
        if button == "C":
            self.clear()
        elif button == "<-":
            self.backspace()
        elif button == "=":
            try:
                result = str(eval(self.equation.get()))
                self.equation.set(result)
            except:
                self.equation.set("Error")
        else:
            self.equation.set(self.equation.get() + button)

    def clear(self):
        self.equation.set("")

    def backspace(self):
        current_equation = self.equation.get()
        self.equation.set(current_equation[:-1])

root = tk.Tk()
calculator = Calculator(root)
root.mainloop()

代码中，我们使用了Tkinter库来创建了一个简单的图形界面计算器，实现了清空和回退功能，并加入了一个带有退出功能的菜单。你可以通过绑定按钮的command属性来实现按钮的功能。同时使用Menu和add_cascade方法创建菜单，并使用add_command方法来添加退出菜单项。