记录python2（一）

# -*- conding：UTF-8 -*-
print 'Now you will input three numbers!'
n1 = int(raw_input('First number: '))
n2 = int(raw_input('Second number: '))
n3 = int(raw_input('Last number: '))
while True:
print '-'* 30
print '菜单：\n1.求3个数的和\n2.取平均值\n3.退出'
print '-'* 30
num = int(raw_input('Please picks: '))
if num == 1:
sum = n1 + n2 + n3
print sum
elif num == 2:
avg = (n1 + n2 + n3)/3
print avg
elif num == 3:
break
else:
print 'Invalid option,try again!'