购物车程序

#!/usr/bin/env python
#_*_coding:utf-8_*_
from  huansuan import  chuli
from  tongji import tongji
flag=True
shengyu=0
a={}
chongzhi = 0
while flag:
    saraly=int(raw_input("充值:").strip())
    if saraly>0:
        chongzhi+=saraly
        shengyu+=saraly
        print "当前余额：%s" %shengyu
    else:
        print"充值金额应大于0"
        continue
    while shengyu>0:
        operation = raw_input("是否继续操作y/n:")
        if operation == "y":
            shangpin = {"iphone": "6000", "MacAir": "15000", "tea": "50", "book": "30"}
            for key in shangpin:
                print "%s  %s" % (key, shangpin[key])
            gm = raw_input("选择购买商品:").strip()
            cl = int(chuli(shengyu,gm))
            if cl < shengyu and cl!=-1:
                shengyu=cl
                tongji(gm,a)
                print "已购买商品：%s    剩余金额：%s" %(a,shengyu)
                continue
            elif cl==shengyu:
                shengyu=cl
                word = raw_input("余额不足，输入c请充值或输入q退出")
                if word == "q":
                    print "购物车中的商品：%s    剩余金额：%s    总计充值金额：%s" % (a, shengyu,chongzhi)
                    saraly=0
                    flag = False
                    break
                else:
                    break
            else:
                print "所选商品不在列表中"
                continue
        elif operation=='n':
            print "欢迎下次光临，您已购买商品：%s    剩余金额：%s" % (a, shengyu)
            flag=False
            break
        else:
             print "请重新输入"
             continue

#_*_coding:utf-8_*_
shangpin = {"iphone": "6000", "MacAir": "15000", "tea": "50", "book": "30"}
def chuli(money,wp):
    if wp in shangpin:
        if int(money)>=int(shangpin[wp]):
            money=int(money)-int(shangpin[wp])
            return money
        else:
            return money
    else:
        return -1

#_*_coding:utf-8_*_
def tongji(wp,yi_gou):
    if wp in yi_gou:
        yi_gou[wp]+=1
    else:
        yi_gou[wp]=1