def main():#主函数
    while True:
        menum()
        choice=int(input('请选择：'))
        if choice in [1,2,3,4,5,6,7]:
            if choice==7:
                answer=input('您确定要退出系统吗？y/n')
                if answer=='y':
                    print('谢谢您的使用')
                    break
                else :
                    continue
            elif choice==1:
                insert()
            elif choice==2:
                search()
            elif choice==3:
                delete()
            elif choice==4:
                modify()
            elif choice==5:
                sort()
            elif choice==6:
                total()
        else:
            print('您输入的有误，请重新输入')
            main()