第4章-8 求分数序列前N项和

n=int(input())

a=[0 for i in range(0,n+10)]

b=[0 for i in range(0,n+10)]

a[1]=2.0

a[2]=3.0

b[1]=1.0

b[2]=2.0

for i in range(3,n+10):

a[i]=a[i-1]+a[i-2]

b[i]=b[i-1]+b[i-2]

sum=0.0

for i in range(1,n+1):

sum+=a[i]/b[i]

print("{:.2f}".format(sum))

第4章-9 查询水果价格

list=input().split(" ")

#print(len(list))

print("[1] apple")

print("[2] pear")

print("[3] orange")

print("[4] grape")

print("[0] exit")

count=0

while count<5:

# print(list[count])

if list[count]=='1':

print("price = {:.2f}".format(3.00))

elif list[count]=='2&#