# 	File: Xiang/entry0.py
#      Ask for a number (1-20) and find 2** n 
#      Try 0.5 result is 1.4142

from graphics import *
WinX,WinY = 500,500    # window geometry

def main():
    win = GraphWin( "Powers of 2", WinX, WinY  )
    Text(Point(50,50), "Enter power of 2(0-20)?:  ").draw(win)
    Text(Point(100,300), " Power of 2:  ").draw(win)
    input = Entry(Point(200,50), 5)
    input.setText("0.0")
    input.draw(win)
    output = Text(Point(200,300),"")
    output.draw(win)

    # wait for a mouse click
    win.getMouse()

    # compute input
    power = eval(input.getText())  # convert to number
    result = 2 ** power

    # display output 
    output.setText("%0.4f" % result)
    #button.setText("Quit")

    # wait for click and then quit
    win.getMouse()
    win.close()
    
main()