from tkinter import *
class Calculator():
    def __init__(self, master=None, **kwargs):
        master.title('CALCULATOR')
        master.geometry('339x400')
        display = StringVar()
        view = Entry(self,highlightthickness= 0, relief=SUNKEN, textvariable=display, border=0, font=('Calibri', 24))
        view.bind('<Return>', lambda e, s=self, w=display: s.calc(w))
        view.place(x=0, y=6, width=254, height=36)
        view.focus_set()
        y,x= 42.5,0
        for key in ('123', '456', '789', 'C0.', '()%'):
            for char in key:
                if char == 'C':
                    self.button(char, x, y, lambda w=display: w.set(''))
                    x += 85
                else:
                    self.button(char, x, y, lambda w=display, c=char: w.set(w.get() + c))
                    x+= 85
            x = 0
            y += 37
        x,y = 255,6
        for char in '=+-*/':
            if char == '=':
                btn = self.button(char, x, y)
                btn.bind('<ButtonRelease>', lambda e, s=self, w=display: s.calc(w))
            else:
                self.button(char, x, y, lambda w=display, s='%s' % char: w.set(w.get() + s))
            y += 37