getline and testing EOF at once

Question

I would like to ask about my problem I tried to read Getline and EOF Question but did not help.

Problem is I have no idea where could be mistake here: Is there some problem with used function ( getline or checking EOF ) ?

If there is no text in text.txt file it says there something was found. But I have no idea why or where I made a mistake ...

What I want is: Search for string and if there is no text in txt file I want it to says EOF or something. It still says - even if file is empty - string I was looking for was found in line one , position one - for example

I am puting there code:

#include <iostream>
#include <fstream>
#include <string>

using namespace std;

int openFile(void);
int closeFile(void);
int getTime(void);
int findTime();
int findDate();
int stringFind(string);
bool getOneLine(void);

string what;
bool ifound = false;
string foundstring;
string filename ;
fstream inputfile;
string sentence ;
size_t found ;
string foundTime ;
string foundDate ;
bool timeIsHere = false;
bool dateIsHere = false;

int iterTime = 0;
int iterDate = 0;
int line = 0;


int main (void){
    sentence.clear();

    cout << " Enter the file name:" << endl;

    openFile();


    while (getOneLine() != false) {
        stringFind("Time");
    }




    cout << "END OF PROGRAM" << endl;
    system("PAUSE");
    ///getTime();
    closeFile();


    system("PAUSE");
}


int closeFile(void) {
    inputfile.close();
    cout << " File: " << filename <<  " - was closed...";
    return 0;
}

int openFile(void) {

    cout << " Insert file name in program directory or full path to desired file you want to edit:"<<endl;
    cout << " Do not use path with a space in directory address or filename ! " << endl;
    cout<<" ";
    getline(cin, filename);

    inputfile.open(filename, ios::in);

    cout <<" file_state: " << inputfile.fail();
    if (inputfile.fail() == 1) {
        cout << " - Cannot open your file" << endl;
    }
    else cout << " - File was openned sucesfully"<< endl;



    return 0;

}


int stringFind(string what) {
    cout << " I am looking for:" << what << endl;

    found = what.find(sentence);
    if (found == string::npos) {
        cout << " I could not find this string " << endl;

    }
    else if(found != string::npos){
        cout << " substring was found in line: " << line + 1 << " position: " << found + 1 << endl << endl;
        ifound = true;
        foundstring = sentence;

    }

    return 0;


}  



bool getOneLine(void) {
    if (inputfile.eof()) {
        cout << "END OF FILE" << endl << endl;
        return false;
    }
    else{
        getline(inputfile, sentence);
        cout << "next sentence is: "<< sentence  << endl;
        return true;
        }
}

I am newbie and I have no one to ask - personally . I tried to edit While cycle and IF's to make sure that I did not make a serious mistake but I have no idea.

I tried it with for example sample.txt and this file was empty.

This may have useful info: https://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong — Galik, Jul 16 '16 at 11:14

score 2 · Answer 1 · edited Jul 16 '16 at 17:19

2

Correct way to use getline() and EOF checking would be like this:

bool getOneLine(void) {
    if (getline(inputfile, sentence)) {
        cout << "next sentence is: "<< sentence  << endl;
        return true;
    }
    if (inputfile.eof())
        cout << "EOF reached" << endl;
    else
        cout << "Some IO error" << endl;
    return false;
}

edited Jul 16 '16 at 17:19

Remy Lebeau

555,201
31
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770

answered Jul 16 '16 at 11:11

Arunmu

6,837
1
24
46

Thank you , I tried to find again some information about getline. I found it returns flag - bit. So I can put it in some let me say - condition , like you put. My mistake was I overlook return values when I was looking for it. I did not know it. Thank you. – naschd Jul 17 '16 at 16:15

score 2 · Accepted Answer · answered Jul 16 '16 at 11:31

Always test whether input succeeded after the read attempt! The stream cannot know what you are attempting to do. It can only report whether the attempts were successful so far. So, you'd do something like

if (std::getline(stream, line)) {
    // deal with the successful case
}
else {
    // deal with the failure case
}

In the failure case you might want to use use eof() to determine whether the failure was due reaching the end of the stream: Having reached the end of file and, thus, std::ios_base:eofbit being set is often not an error but simply the indication that you are done. It may still be an error, e.g., when it is known how many lines are to be read but fewer lines are obtained.

Yes, you right. Thanks for this notice. I did not know - probably I overlooked that it has 4 or more flags that getline returns. And with "If" it can continue only with good bit - 0 value. Thank you I appreciate your help and time. — naschd, Jul 17 '16 at 16:31

score 0 · Answer 3 · answered Jul 16 '16 at 11:08

0

You have one mistake here:

found = what.find(sentence);

You are seeking inside of what for the sentence. If sentence is empty, it will be found.

Change it to

found = sentence.find(what);

You should definitivly learn how to use a debugger. That way you would find such issues pretty fast!

answered Jul 16 '16 at 11:08

Nidhoegger

4,973
4
36
81

Yes thank you. There was a root cause of my problem. You right. But SW I am using is new for me , I will learn it asap. So thank you again ;) Hope this thread will help someone with similar problem. – naschd Jul 17 '16 at 16:28

getline and testing EOF at once

3 Answers3