from tkinter import * 
reset=True 
def buttonCallBack(event): 
 global label 
 global reset 
 num=event.widget['text'] 
 if num=='C': 
  label['text']="0" 
  return 
 if num in "=": 
  label['text']=str(eval(label['text'])) 
  reset=True 
  return 
 s=label['text'] 
 if s=='0' or reset==True: 
  s="" 
  reset=False 
 label['text']=s+num 
#主窗口 
root=Tk() 
root.wm_title("計算器") 
#顯示欄1 
label=Label(root,text="0",background="white",anchor="e") 
label['width']=35 
label['height']=2 
label.grid(row=1,columnspan=4,sticky=W) 
#按鈕 
showText="789/456*123-0.C+" 
for i in range(4): 
 for j in range(4): 
  b=Button(root,text=showText[i*4+j],width=7) 
  b.grid(row=i+2,column=j) 
  b.bind("<Button-1>",buttonCallBack) 
showText="()" 
for i in range(2): 
 b=Button(root,text=showText[i],width=7) 
 b.grid(row=6,column=2+i) 
 b.bind("<Button-1>",buttonCallBack) 
b=Button(root,text="=") 
b.grid(row=6,columnspan=2,sticky="we") 
b.bind("<Button-1>",buttonCallBack) 
root.mainloop()