#coding=gbk
#嵩天老师的零基础Python笔记：https://www.bilibili.com/video/av15123607/?from=search&seid=10211084839195730432#page=25 中的35-37讲
# 处理多个银行账户的程序
"""
def addInterest(balances,rate):
for i in range(len(balances)):
balances[i] = balances[i] * (1 + rate)
def test():
amounts = [1000, 105, 3500, 739]
print(id(amounts)) #实参amounts内存地址
rate = 0.05
addInterest(amounts,rate) #实参amounts在调用函数时发生了改变
print(id(amounts)) #实参amounts内存地址没有发生改变
print(amounts)
amounts.append(700)
print(id(amounts)) #实参amounts内存地址没有发生改变
print(amounts)
test()
"""
#程序模块化例子
#程序1：
"""
print("This program plots the growth of a 10-year investment.")
principal = eval(input("Enter the initial principal: "))
apr = eval(input("Enter the annualized interest rate: "))
for year in range(1,11):
principal = principal * (1 + apr)
print("%2d" % year, end='')
total = int(principal*4/1000)
print("*" * total)
print("0.0K 2.5K 5.0K 7.5K 10.0K")
"""
#对程序1进行模块化
"""
def creatTable(principal, apr):
for year in range(1,11):
principal = principal * (1 + apr)
print("%2d" % year, end='')
total = caculateNum(principal)
print("*" * total)
print("0.0K 2.5K 5.0K 7.5K 10.0K")
def caculateNum(principal):
total = int(principal*4/1000)
return total
def main():
print("This program plots the growth of a 10-year investment.")
principal = eval(input("Enter the initial principal: "))
apr = eval(input("Enter the annualized interest rate: "))
creatTable(principal,apr)
main()
"""
# python的参数是通过值还传递的
# 如果变量是可变对象，返回到调用程序后，该对象会呈现被修改后的状态。
# 递归定义的特征：
# 有一个或多个基例是不需要再次递归的
# 所有的递归链都要以一个基例结尾
# 递归每次调用都会引起新函数的开始
# 递归有本地值的副本，包括该值的参数
# 阶乘递归函数中，每次函数调用中的相关n值在中途的递归链暂时存储，并在函数返回时使用。
# 阶乘的递归定义函数：
"""
def fact(n):
if n == 0:
return 1
else:
return n * fact(n-1)
"""
# 字符串反转递归函数
def reverse(s):
if s == "":
return s
else:
return reverse(s[1:]) + s[0]
print(reverse("iloveyou"))
#
# turtle库的常用指令
# forward(distance)将箭头移到某个指定坐标
# left(angel) right(angel)
# penup()提起笔，用于另起一个地方绘制时用，与pendown()配对使用。
# goto(x,y)
# home()
# circle(radius)
# speed()
#
# 用turtle库绘制并填充一个五角星的程序
"""
from turtle import Turtle
p = Turtle()
p.speed(1)
p.pensize(5)
p.color("black","yellow")
p.begin_fill()
for i in range(5):
p.forward(200)
p.right(144)
p.end_fill()
"""
# 用递归函数画树：
from turtle import Turtle
def maketree(x,y):
p = Turtle()
p.speed(0.1)
p.color("green")
p.pensize(5)
p.hideturtle()
p.getscreen().tracer(30,0)
p.left(90)
p.penup()
p.goto(x,y)
p.pendown()
t = tree([p],110,65,0.6375)
print(len(p.getscreen().turtles())) #用了多少个turtle绘制
def tree(plist, l, a, f):
if l > 5:
lst = []
for p in plist:
p.forward(l)
q = p.clone()
p.left(a)
q.right(a)
lst.append(p)
lst.append(q)
tree(lst, l*f, a, f)
def main():
maketree(-200, 200)
maketree(0, 0)
maketree(200, -200)
main()