multiple lines in a string

I created a program that accepts input from the keyboard and stores it in a string. Then it outputs the string in a file. This works, and is as follows:

Code:

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

int main()
{
	string sentence;
	ofstream file;
	char filename[100];	

	cout << "Enter text to be written to file: ";
	getline(cin, sentence);
	cout << endl;
	cout << "The text will be written to the current directory (contains the .cpp file)." << endl;
	cout << "The file will be called Output.txt" << endl;	
	file.open("Output.txt", ios::out);
	file << sentence;	
	
	
	file.close();
	cout << endl;
	cin.get();
	cout << endl;
	return 0;
}

The problem:
In unix, I have to redirect the stdin to a file (a.out < file.txt). So, I want this to read all the contents of "file.txt" into the string. However, only the first line of the file is being read into string. I think it probably has something to do with getline, but i'm not sure how to fix it. I thought getline is suppose to include all whitespace, but maybe it has something to do with unix (\n or endl?).
By the way, I'm trying to use a string instead of a char.

This is an example of the file:

Code:

This is sample text that needs
to be read correctly. More sample
text is as follows.

Only the first line reads into the string.


Thanks.

Well, getline gets a line (unintuitive name, I know). If you want everything, then you can call getline multiple times (until a read fails).

getline allows you to choose a delimiter (the default is newline).
Pick a character which isn't in the file, and you should get the whole file in your string.

Originally Posted by Cpro

I think it probably has something to do with getline, but i'm not sure how to fix it. I thought getline is suppose to include all whitespace, but maybe it has something to do with unix (\n or endl?)

getline will copy up until it reads a newline character and then stops... hence the name getline.

Ok, i thought getline read multiple lines.
Anyways, what would be the best way to read all the text into the string, without haveing to output each line before the next. For exaple, i tried

Code:

while(1)
	{		
		getline(cin, sentence);
		if(getline(cin, sentence).fail()) break;
	}

This will overwrite the string everytime a new line is encountered. So, i would have to output each line before it is over-written. However, I would like to read all the lines into the string, so it's one long string that can be output at the end of the program (maybe this is not possible?).
Also, if i use this with the keyboard (instead of file) as input, the while loop will never break. It does with the file.

Thanks.

Use cin.rdbuf():

Code:

        string_stream writeMe;
        cout << "Enter text to be written to file: ";
	file.open("Output.txt", ios::out);
        file << cin.rdbuf();
	cout << "The text will be written to the current directory (contains the .cpp file)." << endl;
	cout << "The file will be called Output.txt" << endl;

To read into a string, read it into a ostringstream then use the str method to get the string, or rdbuf to get the buffer.

Ok, i got it working now. Thanks.
One more question.

I have to make a program that takes names from input (the keyboard) and outputs them in reverse order (to the screen). This works, and is as follows:

Code:

int main()
{
	string name;
	string tempName;
	string nameArray[5];
	int nameSize;

	
	//cout << "Enter five names: " << endl;
	for(int i = 0; i < 5; i++)
	{
		cin >> name;
		nameArray[i] = name;
	}

	cout << endl;
	
	//cout << "The names are: " << endl;
	for(int j = 0; j < 5; j++)
	{
		tempName = nameArray[j];
		nameSize = tempName.size()-1;

		while(nameSize >= 0)
		{
			cout << tempName[nameSize];
			nameSize--;
		}		
		cout << endl;
	}

	cout << endl;
	cin.get();
	cout << endl;
	return 0;
}

The problem:
I have to use unix commands to direct input and output to and from files (ex: a.out > file1.txt). Is there a way to ouput only the names to the file, instead of the prompts ("Enter five names: ")? Because, when i direct the output, it will print all the cout statements to the file. Then when i direct that file as input (a.out < file1.txt) the prompt will be read into a name. So, i'm trying to figure out a way to only print the names to the output file, while still prompting the user on the screen.

Thanks.

If you write to std::cerr instead of std::cout, that output won't get redirected. (Yes, it's a bit of an abuse, since cerr is supposed to be the error console, but whatever.) OTOH: If you're planning to redirect input as well, why print the prompt? (And note that you won't be able to tell, programmatically, that std::cin is all of a sudden infile.txt.)

That works. Thanks.

"OTOH: If you're planning to redirect input as well, why print the prompt? "

The program has to work both ways (using the screen and a file for input).


Thanks.

I'd recommend using clog instead of cerr. It's a little faster since the output is buffered, but otherwise the behavior is the same.