Thread: while (cin) loop problems

You have to determine when you want to stop reading data from the keyboard. As it is now, your while loop continues until there is a stream error. A stream error will cause the stream object returned by the operator>>, i.e. cin, to evaluate to false, and terminate the while loop. End-of-file is considered a stream error, but unlike with a file, there's no automatic end of file marker in keyboard input--hitting Return just enters a \n in the input stream, which can be read in or skipped with the >> operator. To produce an eof marker from the keyboard, the user has to hit ctrl Z, or return + ctrl Z, or even return + ctrl Z twice.

Thanks for the quick reply.

Is there any way to read in and process multiple words from the same line and then return to a menu? More specifically, I wrote a small proggy that searches a dictionary file for a match to a word that the user inputs. I would like to be able to enter multiple words on the same line seperated by spaces and have the proggy reply with whether or not each word is in the dictionary. Currently I can do this, but between words the proggy still displays the "Enter a word:" message. I would like it to reply for each word and then display "Enter a word:" again.

Heres my current code for this working program:

Code:

#include <stdio.h>
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

ifstream fin;
char fname[32];
char string1[64];
char string2[64];
int result;
int result2;
int search();

int main(int argc, char *argv[])
{
	while (1==1)
	{
		cout << "Enter the word:";
		search();
	}
	
	return 0;
}

int search()
{
	int match = 0;

		cin >> string1;
		fin.open("dictionary.txt", ios::in);
		while( !fin.eof() ) 
		{
		
			fin >> string2;
			result = _stricmp( string1, string2 );
			if (result == 0)
			{
				match = 1;
				cout << string1 << " is a valid word\n\n";
			}
				

		}
		if (match != 1)
		{
			cout << string1 << " is not a valid word\n\n";
		}
		fin.close();
		fin.clear();
		return 0;

}

You don't need <stdio.h>, and if you did, in C++ it should be <cstdio>. (You do need <cstring>, though, for _stricmp() (which is non-standard; you must be using MSVC).)

Code:

while (1==1)

There's no need to use 1==1. You can use 1. (Or for( ; ; ).)

As for your problem, you could use getline() and then separate the string into tokens.

I would also add that you should never make an infinte loop like that.

Consider reasons why you might want to leave that loop. What if your input stream fails? Can you think of a way to say, "If cin fails, exit the loop?"

Besides exit().

And I don't think you should call clear() on a close()ed stream.