Am i using ifstream::fail() method in bad way?

Question

I have the txt file which contains for example:

Arthur 20

Mark 21

Josh 12

The are no empty lanes between, its only for readability!

What I want to do is write it on the screen in the same way as it is in the file.

I tried to make it this way:

ifstream file;
string word;

file.open("data.txt");
while(!file.eof()){

    file >> word;

    if(file.fail())
    break;

    cout << word << " ";
    file >> word;
    cout << word << endl;
}

But the output is:

Arthur 20

Mark 21

Josh 12

0

So why this 0 is being caught as a empty line to my string variable? I thought that fail() should stop the loop and leave me with correct output?

Related [Why is iostream::eof inside a loop condition considered wrong?](http://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong) — Borgleader, Dec 16 '16 at 18:03
Also, your loop condition is checking `data`, but youre reading from `file`? — Borgleader, Dec 16 '16 at 18:04
data.txt is just the name of text file which is handled by data variable. — Slajni, Dec 16 '16 at 18:06
`while(!data.eof()){` <--- this is the file name? that does not make much sense — Borgleader, Dec 16 '16 at 18:07
Anyways can i use any method to do this? I remember that someway i did it few months ago when using the fail() method. — Slajni, Dec 16 '16 at 18:11
I mean the solution in the post you looks like fixes problem only for disposable read. — Slajni, Dec 16 '16 at 18:12
if open succeeds then the body of while is executed then checking again inside loop for opening is bad thing and redundant. there's an alternative to this: `while( getline(file, word ) ){ cout << word << endl; }` — Raindrop7, Dec 16 '16 at 18:29
Sure, but here i have the name and integer for age for example. — Slajni, Dec 16 '16 at 18:32
I mean I want to get Name for string, then get age to the same string. But all these should be at one iteration. — Slajni, Dec 16 '16 at 18:34
ok then read the first as a string and the second as an integer — Raindrop7, Dec 16 '16 at 18:34
But can't i read the number as a string? I want to use one string variable only. — Slajni, Dec 16 '16 at 18:35
`string word; int age; while( file >> word) { file >> age; cout << word << " " << age << endl; }` — Raindrop7, Dec 16 '16 at 18:37
Yeah, i know. But I'm wondering if i can use only this one "word" variable to read word AND age. — Slajni, Dec 16 '16 at 18:40

score 0 · Accepted Answer · answered Dec 16 '16 at 18:40

as long as you have names which don't contain white spaces and age as integer then you can read name as a string and age as an integer.

you don't need to check whether the file was successfully opened or not you can just abbreviate the operation:

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


int main()
{

    std::ifstream file;
    std::string   word;
    int age;

    file.open("data.txt");

    while( file >> word)
    {
        file >> age;
        std::cout << word << "   " << age << std::endl;
    }


    std::cout << std::endl;
    return 0;
}

if you want to use one variable and for sure a string one then:

while( file >> word)
{
    std::cout << word << "   ";
    file >> word;
    std::cout << word << std::endl;
}

I don't see any good thing to read age as a string and maybe later convert it back to an integer!

the output:

Arthur   20
Mark   21
Josh   12

Am i using ifstream::fail() method in bad way?

1 Answers1