1.引言

操千曲而后晓声，观万剑而后识器——————《文心雕龙》

什么意思？用人话来说就是程序员是练出来的，不是看出来的，更不是空想出来的。只要有足够的代码量，连小盆友都能接项目，下面就是分享的一些基础习题。

2.习题

2.1.Demo1

"""
三、循环语句

Demo37
"""

import random
key = int(random.randint(0,101))
print("请猜测一个0~100的数（n结束）")
while True:
	num = input("你的猜测：")
	if num == "n":
		print("结束")
		break
	num = int(num)
	if num == key:
		key2 = input("恭喜你猜对了！再来一把？y/n\n")
		if key2 == "n":
			break
	else:
		if num < key:
			print("小了。")
		else:
			print("大了。")

2.2.Demo2

"""
三、循环语句

Demo38
"""
k = 1
flag = 0
print("找A , B 最大公约数：")
num1 = int(input("A的值："))
num2 = int(input("B的值："))
if num1 > num2:
	num1,num2 = num2,num1         
while k <= num1:
	if num1 % k == 0 or num2 % k ==0:
		flag = 1
		ged = k
	k += 1
if flag == 1:
	print("A和B两数的最大公约数为：{}".format(ged))
else:
	print("A和B没有公约数。")

2.3.Demo3

"""
三、循环语句

Demo39
"""
import math
import random
num = 0
for i in range(1000000):
	x = random.random() * 2 - 1
	y = random.random() * 2 - 1
	if math.sqrt(x ** 2 + y ** 2) < 1:
		num += 1
print("PI为：", num * 4 / 1000000)

2.4.Demo4

"""
三、循环语句

Demo40
"""
num = float(input("请输入一个不为零的数："))
sum = 0
posi = 0
nega = 0
total = 0
while num != 0:
	sum += num
	if num < 0:
		nega += 1
	else:
		posi += 1
	total += 1
	num = float(input("请输入一个不为零的数："))
print("正数：{}\n".format(posi))
print("负数：{}\n".format(nega))
print("总数：{}\n".format(total))
print("平均数值：{}\n".format(sum / total))

2.5.Demo5

"""
三、循环语句

Demo41
"""
num = int(input("请输入一个整数："))
if num < 2:
	print(" ", num, " \n")
while num > 1:
	i = 2
	while num % i != 0:
		i += 1
	print("{} ".format(i),end=" ")
	num /= i

2.6.Demo6

"""
三、循环语句

Demo42
"""
num = int(input("请输入一个数："))

for i in range(1, num + 1):
	k = i
	for j in range(num - i):
	 	print(end = "   ")
	for j in range(1, i * 2):
		if j == 1 or j == i * 2:
	 		print("{}".format(i),end="  ")
		else:
			if j <= i:
				k -= 1
				print("{}".format(k),end="  ")
			else:
				k += 1
				print("{}".format(k),end="  ") 		
	print("")

2.7.Demo7

"""
三、循环语句

Demo43
"""
#模式一
# num = int(input("行数："))
# for i in range(num):
# 	for j in range(i + 1):
# 		print(j+1,end="  ")
# 	print("")
	
#模式二
# num = int(input("行数："))
# for i in range(num , 0 , -1):
# 	for j in range(i):
# 		print(j+1,end="  ")
# 	print("")

#模式三
# num = int(input("行数："))
# for i in range(num):
# 	for j in range(num - (i + 1)):
# 		print(end ="  ")
# 	for j in range(i + 1 , 0,-1):
# 		print(j , end = " ")
# 	print("")

#模式四
num = int(input("行数："))
for i in range(num , 0, -1):
	for j in range(num - (i)):
		print(end ="  ")
	for j in range(i):
		print(j + 1, end = " ")
	print("")

2.8.Demo8

"""
三、循环语句

Demo44
"""
num = int(input("行数："))
for i in range(num):
	for j in range(num - i -1):
		print(end = "    ")
	for j in range(i * 2 - 1):
		if j == 0 or j == i * 2 - 2:
			print("1", end = "   ")
		else:
			if j < i:
				print(2 ** j, end = "   ")
			else: 
				print(2 ** (i - j + 1),end = "   ")
	print("")

2.9.Demo9

"""
三、循环语句

Demo45
"""
k = 0
for i in range(2,1001):
	flag = 1
	for j in range(2,i):
		if i % j == 0:
			flag = 0
			break
	if flag == 1:
		if i < 10:
			print(i, end = "    ")
		elif i < 100:
			print(i, end = "   ")
		else:
			print(i, end = "  ")
		k += 1
		if k % 8 == 0 and k != 0:
			print("")

2.10.Demo10

"""
三、循环语句

Demo46
"""
# i = 10000
# i = 20000
i = 30000
PI = 0
sum = 0
for j in range(1 , i + 1):
	sum += (-1) ** (j + 1) / (2 * j - 1)
PI = sum * 4
print(PI)

2.11.Demo11

"""
三、循环语句

Demo47
"""
i = 10
# i = 20000
#i = 100000
e = 1
for j in range(1 , i + 1):
	item = 1
	for k in range(1 , j + 1):
		item /= k
	e += item
print(e)

2.12.Demo12

"""
三、循环语句

Demo48
"""
for i in range(2, 10000):
	sum = 0
	for j in range(1,i):
		if i % j == 0:
			sum += j
	if sum == i:
		print(i,end = "  ")

2.13.Demo13

"""
三、循环语句

Demo49
"""
import random
k = ["剪刀","石头","布"]
print("=" * 53)
print(" " * 14, "剪刀石头布三局两胜制：")
print("=" * 53)
i = 0
me = 0
it = 0
while True:
	print("当前你赢了",me,"次\n")
	print("当前电脑赢了",it,"次\n")
	i = int(input("（1）剪刀   （2）石头  （3）布：\n"))
	computer = k.index(random.choice(k))
	print("计算机出",k[computer])
	if i == computer + 1:
		print("平局！")
	else:
		if i == 1:
			if (computer + 1) == 2:
				print("电脑赢了这一把！")
				it += 1
			else:
				print("你赢了这一把！")
				me += 1
		elif i == 2:
			if (computer + 1) == 3:
				print("电脑赢了这一把！")
				it += 1
			else:
				print("你赢了这一把！")
				me += 1
		else:
			if (computer + 1) == 1:
				print("电脑赢了这一把！")
				it += 1
			else:
				print("你赢了这一把！")
				me += 1
	if me == 3 or it == 3:
		print("游戏结束！")
		if me == 3:
			print("胜利者是你")
		else:
			print("胜利者是电脑")
		break

2.14.Demo14

"""
三、循环语句

Demo50
"""
nums = []
max = 0
while True:
	num = int(input("输入一个数（0结束）："))
	nums.append(num)
	if num == 0:
		count = nums.count(max)
		break
	if max < num:
		max = num

print("输入的数字中最大值为",max)
print("输入的最大数字出现了",count,"次")

2.15.Demo15

"""
三、循环语句

Demo51
"""
bio = []
num = int(input("请输入一个十进制整数："))
while num > 0:
	bio += str(num % 2)
	num //= 2

bio.reverse()
print("该数二进制表示为：")
for i in range(len(bio)):
	print(bio[i],end="")

2.16.Demo16

"""
三、循环语句

Demo52
"""
six = []
num = int(input("请输入一个十进制整数："))
while num > 0:
	six += str(num % 16)
	num //= 16

six.reverse()
print("该数16进制表示为：")
for i in range(len(six)):
	print(six[i],end="")

2.17.Demo17

"""
三、循环语句

Demo
53
"""
import math
import random
#为了减少错误用自定义函数
##求三角形面积
#已知3为（0，0） （1，0） （0，1）
def s(ax,ay,bx,by,cx,cy):
	area = abs((ax * (by - cy) + bx * (cy - ay) + cx * (ay - by)) / 2.0)
	return area

s0 = s(0,0,1,0,0,1)
num = 0
for i in range(1000000):
	x = random.random() * 2 - 1
	y = random.random() * 2 - 1

	s1 = s(x,y,0,0,1,0)
	s2 = s(x,y,0,0,0,1)
	s3 = s(x,y,1,0,0,1)
	if x <= 0:
		num += 1
	if  (s1 + s2 + s3) == s0:
		num +=1
		
print("落到奇数区域概率为：", num / 1000000)

2.18.Demo18

"""
三、循环语句

Demo54
"""
k = 0
for i in range(2001,2100):
	if i % 400 == 0 or (i % 4 == 0 and i % 100 != 0):
		print(i,end="  ")
		k += 1
		if k % 10 == 0 and k != 0:
			print("")