初級.Net面試題
一、請用Javascript寫一個方法,替換字串中指定位置的字元。
///source原始字串
///index被替換字串的位置
///newchar要替換字元
function replaceEx(source,index,newchar)
{
}
程式碼如下:
function replaceEx(source, index, newchar) {
if (index < 0 || index >= source.length || source.length == 0) {
return "無效的引數";
}
var indexbegin = 0, indexend = source.length;
var sFrontPart = source.substr(indexbegin, index);
var sTailPart = source.substr(index + 1, source.length);
var result = sFrontPart + newchar + sTailPart;
return result;
}
alert(replaceEx('abcdefg',1,'p'));
(注意:substr()為擷取字串方法)
二、資料庫中兩張表,表結構如下
資料庫:sqlserver 2008 r2
表A:id(int),name(nvarchar(20)),age(int),mobile(nvarchar(20)),createtime(datetime)
表B:name(nvarchar(20)),mobile(navarchar(20)),age(int)
問題:請寫一條sql,篩選表A中age值在18~25之間的資料,放到B中並試以createtime排序
select * from (select A.createtime,B.* from A,B where A.age=B.age) as t where t.age between 18 and 25 order by t.createtime asc;
select a.createtime,b.* from A as a inner join B as b on(a.name=b.name) where b.age between 18 and 25 order by a.createtime desc
select a.createtime,b.* from A as a left outer join B as b on a.age=b.age where b.age between 18 and 25 order by a.createtime desc
select b.*,a.createtime from B as b right outer join A as a on b.age=a.age where b.age between 18 and 25 order by a.createtime desc
三、請看以下C#程式碼,並寫出輸出結果並說明原因
static void Main(string[] args)
{
Task.Factory.StartNew(()=>{
Thread.Sleep(2000);
Console.WriteLine(“function1”);
});
var f2=Task.Factory.StartNew(()=>{
return “function2”;
});
Console.WriteLine(f2.Result);
var r3=“r3”;
var f3=Task.Factory.StartNew(()=>{
r3=“function3”;
});
Console.WriteLine(r3);
Console.Readkey();
}