摘要： 1.查询null值 is null 与 ' '的区别 is null ：从未录入过数据，没有地址 ' ' ：录入过数据，而后被删除，是有地址 2.在查询中使用常量列 select UserId as 用户号，PayWay as 付款方式，PayMoney as 付款金额， '天猫' as 购物网站 阅读全文

摘要： 题目描述 ACboy was kidnapped!! he miss his mother very much and is very scare now.You can't image how dark the room he was put into is, so poor :(. As a s 阅读全文

摘要： 快速求幂取模 积的取余等于取余的积取余 代码如下： int pow(int a,int n,int b)//返回值是a的n次方对b取余后的值 { int result=1; a=a%b;//积的取余等于取余的积取余 while(n>0) { if(n%2==1) result=result*a%b; 阅读全文