I/O help

I am working on an exercise that has me ask the user for the name of a text file and then display the just the first 10 lines of it. If there is 10 lines or less, I have to tell the user the entire file has been displayed. This is what I have written.

Code:

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main()
{
	fstream dataFile;
	string buffer;
	string filename;
	int count;

	cout << "Please enter the name of the file: ";
	getline(cin,filename);
	dataFile.open(filename.data(), ios::in);
	if (!dataFile)
	{
		cout << "The file " << filename << " could not be opened" << endl;
		exit(1);
	}
	for (count = 1; count < 9; count++);
	getline(dataFile,buffer);
	cout << buffer[count] << endl;

	dataFile.close();
}

I know there is a way to do it by just typing

Code:

	getline(dataFile,buffer);
	cout << buffer[count] << endl;

10 times but I want to do it this way. If I take out the loop the program works so I know that is the only problem.

Currently your for-loop does the statement ";" nine times. You probably want it to do the statement

Code:

{
getline(dataFile,buffer);
cout << buffer[count] << endl;
}

instead.

Originally Posted by tabstop

Currently your for-loop does the statement ";" nine times. You probably want it to do the statement

Code:

{
getline(dataFile,buffer);
cout << buffer[count] << endl;
}

instead.

If I do that it just prints the third character on the line.

That's because I wasn't paying attention and/or I copied your code. It actually gives you the first character of the first line, the second character of the second line, etc... You should just print buffer whole.

Originally Posted by tabstop

That's because I wasn't paying attention and/or I copied your code. It actually gives you the first character of the first line, the second character of the second line, etc... You should just print buffer whole.

Ok, thanks. I was just trying to challenge myself.

Now I'm having another problem. I just repeated

Code:

	getline(dataFile,buffer);
	cout << buffer[count] << endl;

but when I do that it will always print 10 lines and will repeat the last line of the file if it is less than 10 lines.

Put "count < 10 && !getline(dataFile,buffer)" in the condition of the for loop. That way the loop will break when the count is ten, or when an error occurs when reading from the file (such as the file having less than 10 lines).

Is this what you want me to do?

Code:

	for (count < 10 && !getline(dataFile,buffer));
	getline(dataFile,buffer);
	cout << buffer[count] << endl;

This gives my syntax errors. It says missing ';' before ')' on the line the for loop is on.

By "in the condition of the for loop" I meant between the two semi colons. So replace your "count < 9" statement.

Also, you'd need to remove it from the for loop body.

And tabstop is correct in his remark. There's just a lot of other things wrong with your code.

Code:

for (count = 1; count < 10 && !getline(dataFile,buffer); count++)
{
    //...
}

That's how for should look like.