Python输入输出练习，运算练习，turtle初步练习

1. 

>>> print("Hello World")
Hello World

2.

>>> name = input("输入姓名：")
输入姓名：郭靖
>>> print ("{}同学，学好python,前途无量!".format(name))
郭靖同学，学好python,前途无量!
>>> print ("{}大侠，学好python,前途无量!".format(name[0]))
郭大侠，学好python,前途无量!
>>> print ("{}哥哥，学好python,人见人爱!".format(name[1]))
靖哥哥，学好python,人见人爱!

3.

n1 = input("请输入第一个数:")
n2 = input("请输入第二个数:")
print(float(n1) + float(n2))

4.

>>> a = float(input("a:"))
a:3
>>> b = float(input("b:"))
b:4
>>> c = float(input("c:"))
c:5
>>> s=0.5*a*b*c
>>> S=(s*(s-a)*(s-b)*(s-c))**0.5
>>> print(S)
725.6031973468695

5.

>>> r = 5
>>> area = 3.1415 * r * r
>>> print(area)
78.53750000000001

6.

import turtle
turtle.pensize(3)
turtle.circle(10)
turtle.circle(20)
turtle.circle(30)
turtle.circle(50)
turtle.circle(80)
turtle.circle(120)

7.

import turtle
turtle.pensize(2)
turtle.color("red")
turtle.forward(100)
turtle.left(144)
turtle.forward(100)
turtle.left(144)
turtle.forward(100)
turtle.left(144)
turtle.forward(100)
turtle.left(144)
turtle.forward(100)
turtle.left(144)
turtle.forward(100)

 8.

import turtle
turtle.pensize(2)
turtle.color("red")
turtle.fillcolor("red")
turtle.begin_fill()
turtle.forward(100)
turtle.left(144)
turtle.forward(100)
turtle.left(144)
turtle.forward(100)
turtle.left(144)
turtle.forward(100)
turtle.left(144)
turtle.forward(100)
turtle.left(144)
turtle.forward(100)
turtle.end_fill()