Reading in from a file with getline() having multiple info on one line get invalid argument error

Question

hello folks im still a beginner to c++ so i apologize in advance. okay so some context is this is a hw assignment for my class we have to make a an array that holds all the books that are being read in from the a txt file then organize them by hashing. the part that im stuck on is reading in the data i cant seem to get it right. the error occurs in load table function, it reads the first line and i put the cout stuff under it to test it out and it does print the first book out but after it throws a invalid argument error.

Input file:

116807#A Tale of Two Cities#Charles Dickens#3.73#9.99#1  
111272#The Iliad#Homer#2.78#9.99#10  
164440#The Great Gatsby#F. Scott Fitzgerald#4.92#9.99#8  
122503#Pride and Prejudice#Jane Austen#3.29#8.99#3  
144303#Little Lord Fauntleroy#Frances Hodgson Burnett#3.09#9.99#1  
170933#Alice's Adventures in Wonderland#Lewis Carroll#2.78#9.99#6  
199097#The Awakening#Kate Chopin#4.12#8.99#1  
177633#Robinson Crusoe#Daniel Defoe#3.49#7.99#2  
111967#Little Women#Louisa May Alcott#4.93#7.99#6  
191745#Emma#Jane Austen#4.91#7.99#8  
135001#Sense and Sensibility#Jane Austen#4.08#8.99#9  
171490#The Wonderful Wizard of Oz#L. Frank Baum#2.96#7.99#4  
127722#Lorna Doone#R. D. Blackmore#3.49#9.99#2  
106853#Jane Eyre#Charlotte Brontë#2.08#7.99#4  
160298#Wuthering Heights#Emily Brontë#3.35#8.99#6  
189814#The Secret Garden#Frances Hodgson Burnett#4.36#9.99#10  
124115#Tales from the Arabian Nights#Richard Francis Burton#3.29#8.99#8  
134195#Through the Looking-Glass#Lewis Carroll#2.04#7.99#9  
182188#Don Quixote of La Mancha#Miguel de Cervantes Saavedra#4.05#8.99#3  
131566#The Man Who Was Thursday#G.K. Chesterton#3.37#9.99#5  
151501#The Napoleon of Notting Hill#G.K. Chesterton#2.71#9.99#8  
119358#The Moonstone#Wilkie Collins#3.97#7.99#5  
121609#The Woman in White#Wilkie Collins#4.45#7.99#6  
166298#Heart of Darkness#Joseph Conrad#3.99#9.99#3  
100260#Lord Jim#Joseph Conrad#3.94#8.99#6  
125968#The Deerslayer#James Fenimore Cooper#4.3#8.99#3  
197942#The Last of the Mohicans#James Fenimore Cooper#3.82#8.99#8  
133821#The Red Badge of Courage#Stephen Crane#2.12#7.99#2  
148590#The Fortunes and Misfortunes#Defoe#2.38#7.99#7             
119790#Bleak House#Charles Dickens#4.79#9.99#7  
197972#A Christmas Carol#Charles Dickens#3.95#7.99#5  
145223#David Copperfield#Charles Dickens#3.6#8.99#7  
136123#Great Expectations#Charles Dickens#4.13#9.99#9  
129094#Oliver Twist#Charles Dickens#2.44#8.99#5  
125226#The Brothers Karamazov#Fyodor Dostoyevsky#2.63#7.99#5  
159590#Crime and Punishment#Fyodor Dostoyevsky#4.59#8.99#8  
197385#The Adventures of Sherlock Holmes#Arthur Conan Doyle#3.72#7.99#8  
142385#The Hound of the Baskervilles#Arthur Conan Doyle#3.85#8.99#1  
128144#The Count of Monte Cristo#Alexandre Dumas#4.35#7.99#6  
163534#The Man in the Iron Mask#Alexandre Dumas#3.11#7.99#3  
175244#Middlemarch#George Eliot#3.18#9.99#3  
101815#Silas Marner#George Eliot#3.33#9.99#8  
189553#The Diary of a Nobody#George Grossmith and Weedon Grossmith#3.25#9.99#3  
130211#Allan Quatermain#Henry Rider Haggard#2.77#8.99#6  
137335#King Solomon's Mines#Henry Rider Haggard#4.95#7.99#8  
197439#Far from the Madding Crowd#Thomas Hardy#3.31#7.99#2  
168872#Tess of the D'Urbervilles#Thomas Hardy#4.94#8.99#6  
139789#The Scarlet Letter#Nathaniel Hawthorne#3.15#8.99#10  
115680#Tanglewood Tales for Girls and Boys#Nathaniel Hawthorne#3.55#7.99#4  
133502#A Wonder-Book for Girls and Boys#Nathaniel Hawthorne#4.08#7.99#2  
177844#The Four Million#O. Henry#4.08#9.99#2  
154849#The Odyssey#Homer#2.31#7.99#5  
195419#The Prisoner of Zenda#Anthony Hope#3.09#7.99#10  
195223#The Hunchback of Notre-Dame#Victor Hugo#3.6#7.99#6  
147317#Les Misérables#Victor Hugo#2#9.99#5  
160597#The Sketch Book of Geoffrey Crayon#Washington Irving#2.04#9.99#1  
141976#The Aspern Papers#Henry James#4.54#7.99#5  
148381#The Turn of the Screw#Henry James#3.65#9.99#10  
178209#The Jungle Book#Rudyard Kipling#3.53#8.99#8  
164607#Kim#Rudyard Kipling#4.22#7.99#7  
170053#The Man Who Would Be King#Rudyard Kipling#3.3#9.99#1  
160444#The Phantom of the Opera#Gaston Leroux#4.85#8.99#9  
108155#The Call of the Wild#Jack London#2.57#9.99#9  
158266#White Fang#Jack London#4.11#9.99#5  
174819#The Princess and Curdie#George MacDonald#2.33#9.99#1  
148762#The Princess and the Goblin#George MacDonald#3.97#7.99#9  
160589#The Prince#Niccolò Machiavelli#2.77#8.99#9  
161200#Moby Dick#Herman Melville#3.6#8.99#8  
145480#Utopia#Thomas More#3.55#7.99#8  
141238#Rights of Man#Thomas Paine#2.26#8.99#8  
161113#Tales of Mystery & Imagination#Edgar Allan Poe#4.93#9.99#5  
168418#Ivanhoe#Sir Walter Scott#2.85#7.99#6  
176563#Waverley#Sir Walter Scott#2.17#8.99#10  
162967#Black Beauty#Anna Sewell#2.69#7.99#4    
104473#Hamlet#William Shakespeare#2.48#8.99#9  
163459#King Lear#William Shakespeare#2.3#9.99#3  
100973#MacBeth#William Shakespeare#3.97#8.99#1  
135231#A Midsummer Night's Dream#Shakespeare#3.03#9.99#1  
162533#Othello, The Moor of Venice#Shakespeare#4.03#9.99#1  
123934#Romeo and Juliet#hakespeare#4.79#9.99#5  
133549#The Taming of the Shrew#Shakespeare#3.49#9.99#1  
115879#The Tempest#William Shakespeare#3.7#7.99#4  
173650#Frankenstein#Mary Shelley#3.29#9.99#7  
110299#The Strange Case of Dr. Jekyll and Mr. Hyde#Robert#2.21#9.99#5  
168244#Kidnapped#Robert Louis Stevenson#4.96#7.99#5  
191560#Dracula#Bram Stoker#4.51#9.99#4  
189551#Uncle Tom's Cabin#Harriet Beecher Stowe#2.05#7.99#9  
159274#Gulliver's Travels#Jonathan Swift#4.13#9.99#6  
122012#Vanity Fair#William Makepeace Thackeray#2.88#9.99#9  
181550#Walden#Henry David Thoreau#2.95#8.99#2  
135690#Anna Karenina#Leo Tolstoy#2.1#9.99#4  
109565#War and Peace#Leo Tolstoy#4.42#9.99#3  
107307#Barchester Towers#Anthony Trollope#2.1#9.99#10  
143127#The Adventures of Huckleberry Finn#Twain#4.87#9.99#6  
116641#The Adventures of Tom Sawyer#twain#2.48#9.99#6  
115974#A Connecticut Yankee in King Arthur's Court#Twain#4.73#9.99#2  
109239#Journey to the Center of the Earth#Jules Verne#3.05#8.99#4  
154189#20,000 Leagues Under the Sea#Jules Verne#3.56#8.99#1  
145898#The Time Machine#H.G. Wells#3.2#7.99#1  
198867#The Age of Innocence#Edith Wharton#2.39#9.99#2  
160811#The Importance of Being Earnest#Oscar Wilde#4.91#8.99#9  
126671#The Picture of Dorian Gray#Oscar Wilde#4.45#7.99#1

Program:

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

using namespace std;

struct book
{
    int bookid;
    string title;
    string author;
    float cost;
    float price;
    int quantity;
};

int getHashKey(int, int);
void clearTable(book[], int);
void loadTable(book[], int);
void loadBook(book[], book, int);


int main()
{
    int  size;
    cout << "Enter size of table!" << endl;
    cin >> size;
    book * arr = new book[size];

    clearTable(arr, size);
    loadTable(arr, size);
    /*for (int i = 0; i < size; i++)
    {
        cout << arr[i].bookid << endl;
    }*/

    delete[] arr;
    return 0;
}
int getHashKey(int key, int max_size)
{
    return key % max_size;
}
void clearTable(book arr[], int size)
{
    for (int i = 0; i < size; i++)
    {
        arr[i].bookid = -1;
    }
}
void loadBook(book arr[], book val, int size)
{
    int key = (val.bookid % size);
    while (arr[key].bookid != -1)
    {
        key = (key + 1) % size;
    }
    arr[key] = val;
}

void loadTable(book arr[], int size)
{
    book tempBook;
    string line;
    char s;
    ifstream myfile;
    myfile.open("inventory.txt");
    if (myfile.is_open())
    {
        while (!myfile.eof())
        {
            //this is the part that reads in the line stopping at the #
            //it reads the first line correct than it throws a invalid 
            //argument error. 
            getline(myfile, line, '#');
            tempBook.bookid = stoi(line);

            getline(myfile, line, '#');
            tempBook.title = line;

            getline(myfile, line, '#');
            tempBook.author = line;

            getline(myfile, line, '#');
            tempBook.cost = stof(line);

            getline(myfile, line, '#');
            tempBook.price = stof(line);

            getline(myfile, line, '#');
            tempBook.quantity = stoi(line);


            cout << tempBook.bookid << endl;
            cout << tempBook.title << endl;
            cout << tempBook.author << endl;
            cout << tempBook.cost << endl;
            cout << tempBook.price << endl;
            cout << tempBook.quantity << endl;







            //add load book


            //loadBook(arr, tempBook, size);


        }
    }

}

[why `while (!myfile.eof())` is wrong](https://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong) — Barmar, Jul 06 '17 at 17:52
Run the program under your debugger, and see what the value of the variable is when it gets the invalid argument error. — Barmar, Jul 06 '17 at 17:54
@Barmar Might even be a dupe if there the error happens on last iteration. OP what does your file look like? — NathanOliver, Jul 06 '17 at 17:54
@NathanOliver I think he said the error happens on the second line, so that would only be if the file is one line long. — Barmar, Jul 06 '17 at 17:55
I suspect there's no `#` after the last field on the line, so the last `getline()` should use newline as the delimiter, not `#`. — Barmar, Jul 06 '17 at 17:55
@Barmar Might i added the list so you can see it and ive tried getline(myfile, line, '\n'); but it still gives me the error and skips half of the list — Jose Aguilera, Jul 06 '17 at 18:12
i replaced myfile.eof() with getline(myfile, line) but it seems to skip every other entry — Jose Aguilera, Jul 06 '17 at 18:37
Can you paste the file as plain text, not an image, so we can copy it for testing? — Barmar, Jul 06 '17 at 19:33
Have you figured out which call is reporting invalid argument yet? What did you discover when you ran the program in the debugger? If you haven't, why not? — Barmar, Jul 06 '17 at 19:35
@Barmar after the .eof change i get no more errors and sorry ill post the text in — Jose Aguilera, Jul 07 '17 at 02:34

score 0 · Accepted Answer · answered Jul 07 '17 at 16:03

The error on the 2nd line happens because the last field of the row doesn't have # after it. So the last getline() should use '\n' as the delimiter, not '#'.

When this is fixe, you get an error is happening after reading the last line, because you're using while (!myfile.eof()). The EOF condition isn't set until after you try to read the file at the end, as explained in Why is iostream::eof inside a loop condition considered wrong?. So it's reading an empty line, then trying to parse it as a number. You should put the first getline() call in the while() condition.

The corrected program is:

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

using namespace std;

struct book
{
    int bookid;
    string title;
    string author;
    float cost;
    float price;
    int quantity;
};

int getHashKey(int, int);
void clearTable(book[], int);
void loadTable(book[], int);
void loadBook(book[], book, int);

int main()
{
    int  size;
    cout << "Enter size of table!" << endl;
    cin >> size;
    book * arr = new book[size];

    clearTable(arr, size);
    loadTable(arr, size);
    /*for (int i = 0; i < size; i++)
    {
        cout << arr[i].bookid << endl;
    }*/

    delete[] arr;
    return 0;
}
int getHashKey(int key, int max_size)
{
    return key % max_size;
}
void clearTable(book arr[], int size)
{
    for (int i = 0; i < size; i++)
    {
        arr[i].bookid = -1;
    }
}
void loadBook(book arr[], book val, int size)
{
    int key = (val.bookid % size);
    while (arr[key].bookid != -1)
    {
        key = (key + 1) % size;
    }
    arr[key] = val;
}

void loadTable(book arr[], int size)
{
    book tempBook;
    string line;
    char s;
    ifstream myfile;
    myfile.open("inventory.txt");
    if (myfile.is_open())
    {
        while (getline(myfile, line, '#'))
        {
            tempBook.bookid = stoi(line);

            getline(myfile, line, '#');
            tempBook.title = line;

            getline(myfile, line, '#');
            tempBook.author = line;

            getline(myfile, line, '#');
            tempBook.cost = stof(line);

            getline(myfile, line, '#');
            tempBook.price = stof(line);

            getline(myfile, line, '\n');
            tempBook.quantity = stoi(line);


            cout << tempBook.bookid << endl;
            cout << tempBook.title << endl;
            cout << tempBook.author << endl;
            cout << tempBook.cost << endl;
            cout << tempBook.price << endl;
            cout << tempBook.quantity << endl;

            //add load book

            //loadBook(arr, tempBook, size);

        }
    }
}

@Bargar Thanks you have been a great help and thank you for your time! — Jose Aguilera, Jul 07 '17 at 18:24

Reading in from a file with getline() having multiple info on one line get invalid argument error

1 Answers1