Live Console Logging

[scooke]

I have a log file that is constantly updated every several milliseconds. It contains lines that either start with a 1 or a 0. I am trying to read it from the beginning and cout the lines that start with a 1 to the console. Then once I am caught to the current time, just listen for a file update and cout new lines as they come in. Each time I reach the end of the file, my program throws an error instead of waiting for the next line to be logged. How can I wait for new updates?

//#include <stdafx.h>
#include <iostream> 
#include <fstream> 
#include <string> 

using namespace std; 

int OpenFile()
{ 
	fstream SampleFile; 
	SampleFile.open ("sample.txt"); 
	//Open the File
	if (SampleFile.is_open()) 
	{ 
		//Create a single character to quit when ready.
		string line="test"; 
		while(line.empty()==false)
		{ 
			//Get lines one by one and only cout those where first character is ==1.
			getline(SampleFile,line);
			char ch=line.at(0);
			if (ch=='1')
			{ 
				cout<<line<<endl; 
			}
		} 
		SampleFile.close(); 		
	} 
	else 
		cout <<"Could not open file."<<endl; 
	return 0; 
} 

int main() 
{ 
	OpenFile(); 
	return 0; 
}

[MiiNiPaa]

getline(SampleFile,line); //last read reads nothing
char ch=line.at(0); //Trying to access nonexisting symbol 

[scooke]

What is the correct way to do it?

[MiiNiPaa]

while( getline(SampleFile,line) )
{
//...
}

[scooke]

Can you show all the code? It sounds like I need to delete some things.

[MiiNiPaa]

while(getline(SampleFile,line))
{ 
	if (line.at(0) == '1')
	{ 
		cout<<line<<endl; 
	}
} 

[scooke]

Thanks so much for that. But the file is being written too. As soon as I run the program, it reads all the way to the last line and gives "Press any key to continue." I need it to continue to print out the upcoming lines that are being logged. That's the real issue. Any ideas?

[MiiNiPaa]

Open file. Read till the end. Remember end position. Close file.
Wait.
Open file. Seek to the remembered position. Read till the end... etc.