principal.py源代码分析

principal = 1000.0   # starting principal，本金

rate = .05           # interest rate，利率

 

print "Year %21s" % "Amount on deposit"#打印的头

 

for year in range( 1, 11 ):

   amount = principal * ( 1.0 + rate ) ** year

   #计算每年的本息和

   print "%4d%21.2f" % ( year, amount )

   #打印每年的本息和