python获取从命令行输入数字的方法

#----------------------------------------
#      Name: numerical_input.py
#     Author: Kevin Harris
# Last Modified: 02/13/04
#  Description: This Python script demonstrates 
#         how to get numerical input
#         from the command line 
#         and use the if-else conditional.
#----------------------------------------
print()
print( "Welcome to the Area calculation program" )
print( "---------------------------------------" )
print()
# Print out the menu:
print( "Please select a shape:" )
print( "1 Rectangle" )
print( "2 Circle" )
print()
# The input function both prompts the user
# for input and fetches it...
shape = int( input( "> " ) )
# Calculate the area...
if shape == 1:
  height = int( input("Please enter the height: ") )
  width = int( input("Please enter the width: ") )
  area = height*width
  print( "The area is", area )
else:
  radius = int( input("Please enter the radius: ") )
  area = 3.14*(radius**2)
  print( "The area is", area )
input( '\n\nPress Enter to exit...' )