#include?
#include?
#include?
#include?
#include?
#include?

//如果是5行，nNum最大為4
void?DeleteOneline（int?nNum?QString?&strall）//
{
????int?nLine=0;
????int?Index=0;
????//算出行數(shù)nLine
????while（Index!=-1）
????{
????????Index=strall.indexOf（‘\n‘Index+1）;
????????nLine++;
????}

????//如果是直接從位置0開(kāi)始刪除\n算一個(gè)字符“abc\nme\ndo“?\n的index是3要?jiǎng)h除3+1個(gè)字符，即index+1個(gè)
????if（nNum==0）
????{
????????int?nIndex=strall.indexOf（‘\n‘）;
????????strall.remove（0nIndex+1）;
????}
????else
????{
????????int?nTemp=nNum;
????????int?nIndex=0nIndex2=0;
????????while（nTemp--）
????????{
????????????//
????????????nIndex=strall.indexOf（‘\n‘nIndex+1）;//這里會(huì)更新nIndex
????????????if（nIndex!=-1）//說(shuō)明是有效的
????????????{
????????????????nIndex2=strall.indexOf（‘\n‘nIndex+1）;
????????????}
????????}
????????//刪除的行不是最后一行（從nIndex+1這個(gè)位置起nIndex2-nIndex個(gè)字符全部抹去）
????????if（nNum????????{
????????????strall.remove（nIndex+1?nIndex2-nIndex）;//不用減一
????????}
????????//刪除的是最后一行（從nIndex起始len-nIndex個(gè)字符全抹去）
????????//不能從nIndex+1處開(kāi)始，
????????else?if（nNum==nLine-1）
????????{
????????????int?len=strall.length（）;
????????????strall.remove（nIndexlen-nIndex）;
????????}
????????else
????????{

????????}

????}
}
void?deleteOnelineInFile（int?nNumLine?QString?&filename）
{
????QString?strall;
????QFile?readfile（filename）;
????if（readfile.open（QIODevice::ReadOnly））
????{
????????QTextStream?stream（&readfile）;
????????strall=stream.readAll（）;
????}
????readfile.close（）;
????DeleteOneline（nNumLine?strall）;

????QFile?writefile（filename）;
????if（writefile.open（QIODevice::WriteOnly））
????{
????????QTextStream?wrtstream（&writefile）;
????????wrtstream<????}
????writefile.close（）;


}
int?main（int?argc?char?*argv[]）
{
????QCoreApplication?a（argc?argv）;
????//QFile?file（“c:\\delline.txt“）;
????deleteOnelineInFile（3QString（“c:\\delline.txt“））;

????return?a.exec（）;
}

?屬性????????????大小?????日期????時(shí)間???名稱(chēng)
-----------?---------??----------?-----??----
?????文件?????????321??2012-06-05?14:40??DeleteOnelineInfile.pro
?????文件???????18905??2012-06-05?17:15??DeleteOnelineInfile.pro.user
?????文件????????6958??2012-06-05?14:42??Makefile
?????文件????????5546??2012-06-05?14:42??Makefile.Debug
?????文件????????5521??2012-06-05?14:42??Makefile.Release
?????目錄???????????0??2012-06-05?17:33??debug\
?????文件???????26112??2012-06-05?17:33??debug\DeleteOnelineInfile.exe
?????文件??????311188??2012-06-05?17:33??debug\DeleteOnelineInfile.ilk
?????文件?????????878??2012-06-05?17:33??debug\DeleteOnelineInfile.intermediate.manifest
?????文件??????617472??2012-06-05?17:33??debug\DeleteOnelineInfile.pdb
?????文件???????46095??2012-06-05?17:33??debug\main.obj
?????文件????????2105??2012-06-05?17:43??main.cpp
?????目錄???????????0??2012-06-05?17:45??release\
?????文件??????446464??2012-06-05?17:33??vc90.pdb