Reading a file, unwanted chars at the end

[halmark6Z]

Hi,

I`m reading chars to a char *buffer

ifstream datafile;
int length;
char * buffer;

try
{	
 datafile.open(filename, ios::binary );
 if(!datafile.is_open())
  return false;

 char * buffer;
 datafile.seekg (0, ios::end);
 length = datafile.tellg();
 datafile.seekg (0, ios::beg);
 // allocate memory:
 buffer = new char [length];
 // read data as a block:
 datafile.read(buffer,length);
 // close file	
 datafile.close();

}
catch(...)
{
 cout<<"\n\nError occurred while reading file\n\n";
}

the contents of the test.txt file

ksjdhafkjasnbdfkjhsdfjbsvdkjsdhgkjdshg
asdasd
asdasd
asdasd
g
g

and this is what the buffer contains

ksjdhafkjasnbdfkjhsdfjbsvdkjsdhgkjdshg
asdasd
asdasd
asdasd
g
gH=.;%D

How do I fix the code to get rid of that rubbish in the end?