c++, need help returning from while-loop

nunchuckie · 11-18-2009, 08:37 PM

Hi guys, I just started practicing C++.
Right now I'm trying to put lines of text to a file one by one manually and then stop puting in text by typing end. The thing is that I don't really know how to put the whole line of text one by one into a file and then stop the input by typing a command like "end"...

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

int main()
{
char filename[30];
string sentence;
int i = 2;

cout << "Name your file: ";
cin >> filename;

ofstream outputfile(filename, ios:

ut);
string text;

cout << endl << "Row 1: ";

while (sentence != "end") // <- Lol!

{
cin >> text;
getline(cin, text);
outputfile << sentence << endl;
cout << "Row " << i << ": ";
++i;
}

... more newb code..

return 0;
}

Any sugestions how i can make this possible?
/nunchuckie

MidSpeck · 11-18-2009, 09:12 PM

Quote:

Originally Posted by nunchuckie

Code:

while (sentence != "end")  // <- Lol! :(
    {
      cin >> text;
      getline(cin, text);
      outputfile << sentence << endl;
      cout << "Row " << i << ": ";
      ++i;   
    }

It's been a /long/ time since I've programmed, but it looks like your while statement is looking at the variable "sentence" to decide whether or not it should exit. The thing is, where do you type stuff _into_ "sentence"? I see a: cin >> text; and a getline(cin, text); but I never see you doing anything with the "sentence" variable.

Mess around with that and see if that helps.

neonsignal · 11-19-2009, 07:25 PM

You are almost there. If you use character arrays instead of STL strings, then you would need to do the string comparison using the standard C library (eg strcmp).

The following example would grab lines and print them until it reaches the line "end". Note that it checks the getline first in case it reaches the end of file (which can be entered using <ctrl-D> from the terminal input):

Code:

#include <iostream>
int main()
{
	std::string text;
	while (std::getline(std::cin, text) && text != "end")
		std::cout << text;
}