第一次课后作业

1.

print("菜单".center(30,'#'))

a=('1.鲁班\n'
   '2.程咬金\n'
   '3.刘备')
print(a)
choice=int(input("请输入你的选项："))

if choice==1:
	print("鲁班")
elif choice==2:
	print("程咬金")
else:
	print("刘备")

2.

year=int(input("请输入年分："))
mouth=int(input("请输入月分："))

if mouth==2:
	if year%4==0 and year%100!=0 or year%400==0:
		print("29天")
	else:
		print("28天")
else:
	if  mouth==(1 or 3 or 5 or 7 or 8 or 10 or 12):
		print("31天")
	else:
		print("30天")

3.

import math

a=float(input("input number:"))
b=float(input("input number:"))
c=float(input("input number:"))


delta=b**2-4*a*c
if delta>0:
	x1=(-b+math.sqrt(b**2-4*a*c))/2*a
	x2=(-b-math.sqrt(b**2-4*a*c))/2*a
	print(x1x2)
elif delta==0:
	x=-b/2*a
	print(x)
else :
	print("no answer")

4.

mouth=int(input("请输入月份："))

if 3<=mouth<=5:
	print("春季")
elif 6<=mouth<=8:
	print("夏季")
elif 9<=mouth<=11:
        print("秋季")
else:
	print("冬季")

5.

a=input("请输入")

if a=="":
	print("erro")
else:
	print("true")