Python之计算器

'''
Function:  tkinter  计算器
'''
import math
import tkinter

root = tkinter.Tk()
root.resizable(width=False, height=False)
'''hypeparameter'''
# 是否按下了运算符
IS_CALC = False
# 存储数字
STORAGE = []
# 显示框最多显示多少个字符
MAXSHOWLEN = 18
# 当前显示的数字
CurrentShow = tkinter.StringVar()
CurrentShow.set('0')

'''按下数字键(0-9)'''


def pressNumber(number):
    global IS_CALC
    if IS_CALC:
        CurrentShow.set('0')
        IS_CALC = False
    if CurrentShow.get() == '0':
        CurrentShow.set(number)
    else:
        if len(CurrentShow.get()) < MAXSHOWLEN:
            CurrentShow.set(CurrentShow.get() + number)


'''按下小数点'''


def pressDP():
    global IS_CALC
    if IS_CALC:
        CurrentShow.set('0')
        IS_CALC = False
    if len(CurrentShow.get().split('.')) == 1:
        if len(CurrentShow.get()) < MAXSHOWLEN:
            CurrentShow.set(CurrentShow.get() + '.')


'''清零'''


def clearAll():
    global STORAGE
    global IS_CALC
    STORAGE.clear()
    IS_CALC = False
    CurrentShow.set('0')


'''清除当前显示框内所有数字'''


def clearCurrent():
    CurrentShow.set('0')


'''删除显示框内最后一个数字'''


def delOne():
    global IS_CALC
    if IS_CALC:
        CurrentShow.set('0')
        IS_CALC = False
    if CurrentShow.get() != '0':
        if len(CurrentShow.get()) > 1:
            CurrentShow.set(CurrentShow.get()[:-1])
        else:
            CurrentShow.set('0')


'''计算答案修正'''


def modifyResult(result):
    result = str(result)
    if len(result) > MAXSHOWLEN:
        if len(result.split('.')[0]) > MAXSHOWLEN:
            result = 'Overflow'
        else:
            # 直接舍去不考虑四舍五入问题
            result = result[:MAXSHOWLEN]
    return result


'''按下运算符'''


def pressOperator(operator):
    global STORAGE
    global IS_CALC
    if operator == '+/-':
        if CurrentShow.get().startswith('-'):
            CurrentShow.set(CurrentShow.get()[1:])
        else:
            CurrentShow.set('-' + CurrentShow.get())
    elif operator == '1/x':
        try:
            result = 1 / float(CurrentShow.get())
        except:
            result = 'illegal operation'
        result = modifyResult(result)
        CurrentShow.set(result)
        IS_CALC = True
    elif operator == 'sqrt':
        try:
            result = math.sqrt(float(CurrentShow.get()))
        except:
            result = 'illegal operation'
        result = modifyResult(result)
        CurrentShow.set(result)
        IS_CALC = True
    elif operator == 'MC':
        STORAGE.clear()
    elif operator == 'MR':
        if IS_CALC:
            CurrentShow.set('0')
        STORAGE.append(CurrentShow.get())
        expression = ''.join(STORAGE)
        try:
            result = eval(expression)
        except:
            result = 'illegal operation'
        result = modifyResult(result)
        CurrentShow.set(result)
        IS_CALC = True
    elif operator == 'MS':
        STORAGE.clear()
        STORAGE.append(CurrentShow.get())
    elif operator == 'M+':
        STORAGE.append(CurrentShow.get())
    elif operator == 'M-':
        if CurrentShow.get().startswith('-'):
            STORAGE.append(CurrentShow.get())
        else:
            STORAGE.append('-' + CurrentShow.get())
    elif operator in ['+', '-', '*', '/', '%']:
        STORAGE.append(CurrentShow.get())
        STORAGE.append(operator)
        IS_CALC = True
    elif operator == '=':
        if IS_CALC:
            CurrentShow.set('0')
        STORAGE.append(CurrentShow.get())
        expression = ''.join(STORAGE)
        try:
            result = eval(expression)
        # 除以0的情况
        except:
            result = 'illegal operation'
        result = modifyResult(result)
        CurrentShow.set(result)
        STORAGE.clear()
        IS_CALC = True


'''Demo'''


def Demo():
    root.minsize(320, 420)
    root.title('Calculator')
    # 布局
    # --文本框
    label = tkinter.Label(root, textvariable=CurrentShow, bg='black', anchor='e', bd=5, fg='white', font=('楷体', 20))
    label.place(x=20, y=50, width=280, height=50)
    # --第一行
    # ----Memory clear
    button1_1 = tkinter.Button(text='MC', bg='#666', bd=2, command=lambda: pressOperator('MC'))
    button1_1.place(x=20, y=110, width=50, height=35)
    # ----Memory read
    button1_2 = tkinter.Button(text='MR', bg='#666', bd=2, command=lambda: pressOperator('MR'))
    button1_2.place(x=77.5, y=110, width=50, height=35)
    # ----Memory save
    button1_3 = tkinter.Button(text='MS', bg='#666', bd=2, command=lambda: pressOperator('MS'))
    button1_3.place(x=135, y=110, width=50, height=35)
    # ----Memory +
    button1_4 = tkinter.Button(text='M+', bg='#666', bd=2, command=lambda: pressOperator('M+'))
    button1_4.place(x=192.5, y=110, width=50, height=35)
    # ----Memory -
    button1_5 = tkinter.Button(text='M-', bg='#666', bd=2, command=lambda: pressOperator('M-'))
    button1_5.place(x=250, y=110, width=50, height=35)
    # --第二行
    # ----删除单个数字
    button2_1 = tkinter.Button(text='del', bg='#666', bd=2, command=lambda: delOne())
    button2_1.place(x=20, y=155, width=50, height=35)
    # ----清除当前显示框内所有数字
    button2_2 = tkinter.Button(text='CE', bg='#666', bd=2, command=lambda: clearCurrent())
    button2_2.place(x=77.5, y=155, width=50, height=35)
    # ----清零(相当于重启)
    button2_3 = tkinter.Button(text='C', bg='#666', bd=2, command=lambda: clearAll())
    button2_3.place(x=135, y=155, width=50, height=35)
    # ----取反
    button2_4 = tkinter.Button(text='+/-', bg='#666', bd=2, command=lambda: pressOperator('+/-'))
    button2_4.place(x=192.5, y=155, width=50, height=35)
    # ----开根号
    button2_5 = tkinter.Button(text='sqrt', bg='#666', bd=2, command=lambda: pressOperator('sqrt'))
    button2_5.place(x=250, y=155, width=50, height=35)
    # --第三行
    # ----7
    button3_1 = tkinter.Button(text='7', bg='#bbbbbb', bd=2, command=lambda: pressNumber('7'))
    button3_1.place(x=20, y=200, width=50, height=35)
    # ----8
    button3_2 = tkinter.Button(text='8', bg='#bbbbbb', bd=2, command=lambda: pressNumber('8'))
    button3_2.place(x=77.5, y=200, width=50, height=35)
    # ----9
    button3_3 = tkinter.Button(text='9', bg='#bbbbbb', bd=2, command=lambda: pressNumber('9'))
    button3_3.place(x=135, y=200, width=50, height=35)
    # ----除
    button3_4 = tkinter.Button(text='/', bg='#708069', bd=2, command=lambda: pressOperator('/'))
    button3_4.place(x=192.5, y=200, width=50, height=35)
    # ----取余
    button3_5 = tkinter.Button(text='%', bg='#708069', bd=2, command=lambda: pressOperator('%'))
    button3_5.place(x=250, y=200, width=50, height=35)
    # --第四行
    # ----4
    button4_1 = tkinter.Button(text='4', bg='#bbbbbb', bd=2, command=lambda: pressNumber('4'))
    button4_1.place(x=20, y=245, width=50, height=35)
    # ----5
    button4_2 = tkinter.Button(text='5', bg='#bbbbbb', bd=2, command=lambda: pressNumber('5'))
    button4_2.place(x=77.5, y=245, width=50, height=35)
    # ----6
    button4_3 = tkinter.Button(text='6', bg='#bbbbbb', bd=2, command=lambda: pressNumber('6'))
    button4_3.place(x=135, y=245, width=50, height=35)
    # ----乘
    button4_4 = tkinter.Button(text='*', bg='#708069', bd=2, command=lambda: pressOperator('*'))
    button4_4.place(x=192.5, y=245, width=50, height=35)
    # ----取导数
    button4_5 = tkinter.Button(text='1/x', bg='#708069', bd=2, command=lambda: pressOperator('1/x'))
    button4_5.place(x=250, y=245, width=50, height=35)
    # --第五行
    # ----3
    button5_1 = tkinter.Button(text='3', bg='#bbbbbb', bd=2, command=lambda: pressNumber('3'))
    button5_1.place(x=20, y=290, width=50, height=35)
    # ----2
    button5_2 = tkinter.Button(text='2', bg='#bbbbbb', bd=2, command=lambda: pressNumber('2'))
    button5_2.place(x=77.5, y=290, width=50, height=35)
    # ----1
    button5_3 = tkinter.Button(text='1', bg='#bbbbbb', bd=2, command=lambda: pressNumber('1'))
    button5_3.place(x=135, y=290, width=50, height=35)
    # ----减
    button5_4 = tkinter.Button(text='-', bg='#708069', bd=2, command=lambda: pressOperator('-'))
    button5_4.place(x=192.5, y=290, width=50, height=35)
    # ----等于
    button5_5 = tkinter.Button(text='=', bg='#708069', bd=2, command=lambda: pressOperator('='))
    button5_5.place(x=250, y=290, width=50, height=80)
    # --第六行
    # ----0
    button6_1 = tkinter.Button(text='0', bg='#bbbbbb', bd=2, command=lambda: pressNumber('0'))
    button6_1.place(x=20, y=335, width=107.5, height=35)
    # ----小数点
    button6_2 = tkinter.Button(text='.', bg='#bbbbbb', bd=2, command=lambda: pressDP())
    button6_2.place(x=135, y=335, width=50, height=35)
    # ----加
    button6_3 = tkinter.Button(text='+', bg='#708069', bd=2, command=lambda: pressOperator('+'))
    button6_3.place(x=192.5, y=335, width=50, height=35)
    root.mainloop()


if __name__ == '__main__':
    Demo()