.NET C++ StreamReader

DateTime dtNow = DateTime::Now;
String^ str = dtNow.ToString("yyyyMMdd");

StreamReader^ cReader = gcnew StreamReader("test.txt", Encoding::Default);
String^ str2 = cReader->ReadToEnd();
cReader->Close();
MessageBox::Show(str2);

DateTime dtNow = DateTime::Now;
String^ logFileName = "log_" + dtNow.ToString("yyyyMMdd") + ".txt";
StreamWriter^ writeLogFile;

if(File::Exists(logFileName)){
    writeLogFile = File::AppendText(logFileName);
    writeLogFile->WriteLine(DateTime::Now);
} else {
    writeLogFile = gcnew StreamWriter(logFileName);
    writeLogFile->WriteLine("A text file is born!");
    writeLogFile->WriteLine(DateTime::Now);
}            
writeLogFile->Close();