from tkinter import *
from tkinter import ttk
def func():
l2.configure(text=cb.get())
win =Tk()
win.title("Aimtocode Python")
win.geometry('200x100')
course=["Java","Python","C","C++","JavaScript","PHP","HTML","CSS"]
l1=Label(win,text="Choose Your Course @ Aimtocode")
l1.grid(column=0, row=0)
cb=ttk.Combobox(win,values=course,width=10)
cb.grid(column=0, row=1)
cb.current(0)
b=Button(win,text="Click Here",command=func)
b.grid(column=0, row=2)
l2=Label(win,text="")
l2.grid(column=0, row=3)
win.mainloop()