16,472
社区成员
发帖
与我相关
我的任务
分享
CStdioFile file("C:\\Users\\lyf\\Desktop\\aa.txt", CFile::modeWrite|CFile::modeCreate);
CString str;
for (int i = 0; i < 30; i ++)
{
str.Format("第%d\r\n", i);
file.WriteString(str);
}
file.Close();
CFile file2("C:\\Users\\lyf\\Desktop\\aa.txt", CFile::modeReadWrite);
long len = file2.GetLength();
char *csBuff = new char[len+1];
memset(csBuff,0, len+1);
file2.Read(csBuff, len);
str = csBuff;
int index = 0;
for (int i = 0; i < 3; i++)//第3行插入
{
index = str.Find("\r\n", index);
index++;
}
index++;;
file2.Seek(index, CFile::begin);
file2.Write("第四行\r\n", strlen("第四行\r\n"));
file2.Write(csBuff+index, strlen(csBuff+index));
file2.Close();
delete csBuff;
csBuff = NULL;
你看下 根据你需要修改。记得给分