编程计算图形的面积。程序可计算圆形、长方形、正方形的面积，运行时先提示用户选择图形的类型，然后，对圆形要求用户输入半径值，对长方形要求用户输入长和宽的值，对正方形要求用户输入边长的值，计算出面积的值后将其显示出来。两种方式

第一种方式：使用Python编写一个控制台程序，实现计算图形面积的功能。代码如下：

import math

print("请选择图形的类型：")
print("1. 圆形")
print("2. 长方形")
print("3. 正方形")

choice = int(input("请输入选项："))

if choice == 1:
    radius = float(input("请输入圆的半径："))
    area = math.pi * radius * radius
    print("圆的面积为：", area)
elif choice == 2:
    length = float(input("请输入长方形的长度："))
    width = float(input("请输入长方形的宽度："))
    area = length * width
    print("长方形的面积为：", area)
elif choice == 3:
    side = float(input("请输入正方形的边长："))
    area = side * side
    print("正方形的面积为：", area)
else:
    print("输入有误，请重新选择")

第二种方式：使用Python和Tkinter编写一个图形界面程序，实现计算图形面积的功能。代码如下：

import tkinter as tk
import math

def calculate_area():
    choice = shape.get()
    if choice == 1:
        radius = float(radius_entry.get())
        area = math.pi * radius * radius
        result_label.config(text="圆的面积为：%.2f" % area)
    elif choice == 2:
        length = float(length_entry.get())
        width = float(width_entry.get())
        area = length * width
        result_label.config(text="长方形的面积为：%.2f" % area)
    elif choice == 3:
        side = float(side_entry.get())
        area = side * side
        result_label.config(text="正方形的面积为：%.2f" % area)
    else:
        result_label.config(text="请选择图形的类型")

window = tk.Tk()
window.title("图形面积计算器")

shape_label = tk.Label(window, text="请选择图形的类型：")
shape_label.grid(row=0, column=0, padx=10, pady=10, sticky=tk.W)

shape = tk.IntVar()
circle_radiobutton = tk.Radiobutton(window, text="圆形", variable=shape, value=1)
circle_radiobutton.grid(row=1, column=0, padx=10, pady=5, sticky=tk.W)

rectangle_radiobutton = tk.Radiobutton(window, text="长方形", variable=shape, value=2)
rectangle_radiobutton.grid(row=2, column=0, padx=10, pady=5, sticky=tk.W)

square_radiobutton = tk.Radiobutton(window, text="正方形", variable=shape, value=3)
square_radiobutton.grid(row=3, column=0, padx=10, pady=5, sticky=tk.W)

radius_label = tk.Label(window, text="请输入圆的半径：")
radius_label.grid(row=4, column=0, padx=10, pady=5, sticky=tk.W)

radius_entry = tk.Entry(window)
radius_entry.grid(row=4, column=1, padx=10, pady=5)

length_label = tk.Label(window, text="请输入长方形的长度：")
length_label.grid(row=5, column=0, padx=10, pady=5, sticky=tk.W)

length_entry = tk.Entry(window)
length_entry.grid(row=5, column=1, padx=10, pady=5)

width_label = tk.Label(window, text="请输入长方形的宽度：")
width_label.grid(row=6, column=0, padx=10, pady=5, sticky=tk.W)

width_entry = tk.Entry(window)
width_entry.grid(row=6, column=1, padx=10, pady=5)

side_label = tk.Label(window, text="请输入正方形的边长：")
side_label.grid(row=7, column=0, padx=10, pady=5, sticky=tk.W)

side_entry = tk.Entry(window)
side_entry.grid(row=7, column=1, padx=10, pady=5)

calculate_button = tk.Button(window, text="计算面积", command=calculate_area)
calculate_button.grid(row=8, column=0, padx=10, pady=10)

result_label = tk.Label(window, text="")
result_label.grid(row=9, column=0, padx=10, pady=10)

window.mainloop()