same word added twice

Question

In C++, I am trying to read through a file and store the strings from that file into a string in the program. This works great until I get to the last word, which is always stored twice.

ifstream inputStream;
string next = "";
string allMsg = "";
inputStream.open(fileName.c_str());
string x;

while (!inputStream.eof())
{
    inputStream >> x;
    next = next + " " + x;
}
cout << "The entire message, unparsed, is: " << next << endl;

Doing this adds the last word or int from the file I open to next. Any suggestions? Thanks!

[`while (!eof())` is wrong.](http://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong) — chris, Oct 15 '13 at 00:39

Zac Wrangler · Accepted Answer · 2013-10-15T00:54:26.460

3

This is because when you read the last line, it won't set eof bit and the fail bit, only when you read the END, eof bit is set and eof() returns true.

while (!inputStream.eof())  // at the eof, but eof() is still false
{
    inputStream >> x;  // this fails and you are using the last x
    next = next + " " + x;
}

change it to

while( inputStream >> x){
    // inputStream >> x;  dont call this again!
    next = next + " " + x;
}

edited Oct 15 '13 at 00:54

answered Oct 15 '13 at 00:47

Zac Wrangler

1,330
8
8

This isn't working because it is now only reading in every other word. So if the file said "one two three four five", it now only stores "one three five" into next. – robertjskelton Oct 15 '13 at 00:51
you don't call `inputStream >> x;` inside the loop... – Zac Wrangler Oct 15 '13 at 00:53

score 0 · Answer 2 · answered Oct 15 '13 at 00:46

0

while (!inputStream.eof())

Should be

while (inputStream >> x)

answered Oct 15 '13 at 00:46

Zac Howland

15,149
1
23
37

@0x499602D2 - that has already been answered many many times: http://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong – Zac Howland Oct 15 '13 at 02:22

score -1 · Answer 3 · answered Oct 15 '13 at 00:46

-1

eof() will return true if the last read hit the end of file, not if the next read will hit the end of file. Try:

ifstream inputStream;
string next = "";
string allMsg = "";
inputStream.open(fileName.c_str());
string x;

inputStream >> x;
if(!inputStream.eof()) {
    do {
        next = next + " " + x;
        inputStream >> x;
    } while (!inputStream.eof())
}
cout << "The entire message, unparsed, is: " << next << endl;

answered Oct 15 '13 at 00:46

Darius Makaitis

850
1
5
5

This should not be the accepted answer. Zac Wrangler's is accurate and more complete. This one is just wrong. – Zac Howland Oct 15 '13 at 03:22

same word added twice

3 Answers3