Library (of books) program

[Hypnotik]

Hello everyone. I'm working on a program which uses a class (Shelf) and a struct (Book). In the main program we declare an array (Library[25]) which is of type shelf. The program takes in various info about books (author, title, isbn, etc) and then allows you to search for books starting with a certain letter, and in turn displays those books and the info on them.

At this point I can enter the info, and display the info for 1 book. I'm confused about where I should look to enter more info. I'm assuming it should be in my main. Do I need to increment i (my counter) at the end of the loop so the info is not copying over itself?

 
#include <iostream>
#include <ctype.h>
using namespace std;
struct book
{
    char title[25],author[25];
    int ISBN,pages,year;
};
class shelf
{
private:
    book books[50];
 
public:
    shelf();
    ~shelf(){};
    void input();
    void output();
    char alpha[2];
    bool full;
};
shelf::shelf()
{
    int i=0;
    cout<<"constructing our shelves"<<endl;
    for(i=0;i<50;++i)
    {
        books[i].title[i]='-';
        books[i].author[i]='-';
        books[i].ISBN=0;
        books[i].pages=0;
        books[i].year=0000;
    }
 
    for (i=0;i<=2;++i)
    {
        alpha[i]='-';
    }
    full=false;
};
void shelf::input()
{
    int sel=0,i=0;
    cout<<"This function allows the input of information for books."<<endl;
    cout<<"What would you like to enter?"<<endl;
    do
    {
        cout<<"1) Enter authors name."<<endl<<"2) Enter the title of the book."<<endl<<"3) Enter the ISBN."<<endl<<"4) Enter the number of pages."<<endl;
        cout<<"5) Enter the year the book was published."<<endl<<"6) Enter all of the information."<<endl;
        cin>>sel;
        switch(sel)
        {
        case 1:
            cout<<"Enter the authors name."<<endl;
            cin.getline(books[i].author,20,'/n');
            cin.ignore();
            break;
        case 2:
            cout<<"Enter the title of the book."<<endl;
            cin.getline (books[i].title,20,'/n');
            cin.ignore();
            break;
        case 3:
            cout<<"Enter the ISBN of the book."<<endl;
            cin>>books[i].ISBN;
            break;
        case 4:
            cout<<"Enter the number of pages."<<endl;
            cin>>books[i].pages;
            break;
        case 5:
            cout<<"Enter the year the book was published."<<endl;
            cin>>books[i].year;
            break;
        case 6:
            cout<<"Enter the authors name."<<endl;
            {
                cin.ignore();
                cin.getline(books[i].author,30,'\n');
                cout<<books[i].author<<endl;
 
            }
            cout<<"Enter the title of the book."<<endl;
            {
                cin.getline (books[i].title,30,'\n');
                cout<<books[i].title<<endl;
            }
            cout<<"Enter the ISBN of the book."<<endl;
            cin>>books[i].ISBN;
            cout<<books[i].ISBN<<endl;
            cout<<"Enter the number of pages."<<endl;
            cin>>books[i].pages;
            cout<<books[i].pages<<endl;
            cout<<"Enter the year the book was published."<<endl;
            cin>>books[i].year;
            cout<<books[i].year<<endl;
            break;
        default:
            cout<<"Make a selection from the menu."<<endl;
            break;
        }
    }
    while (sel<1||sel>6);
 
}
void shelf::output()
{
    int i=0;
    char let;
    cout<<"Enter the letter for which you would like to display titles: "<<endl;
    cin>>let;
    let=toupper(let);
    if (books[i].title[i]==let)
    {
        cout<<"Author         Title        ISBN        #Pages          Published"<<endl;
        cout<<books[i].author<<"       "<<books[i].title<<"       "<<books[i].ISBN<<"       "<<books[i].pages<<"       "<<books[i].year<<endl;
    }
    else
    cout<<"No book titles found which begin with the letter "<<let<<endl;
}
void main()
{
    char ans='Y';
    int i=0;
    shelf library[25];
    do
    {
        cout<<"Do you have a book to enter? Enter Y for yes or # for no."<<endl;
        cin>>ans;
        ans=toupper(ans);
        library[i].input();
        library[i].output();
        ++i;
    }
    while (ans!='#');
//    library[i].output();
    cout<<"Exiting program."<<endl;
}
 
 

Thanks,
J

[Hypnotik]

Got it, I was trying to count the books added in main (or atleast I was planning to). I am assuming in the constructor I need to initialize the num_books variable, and then I will increment it within the input function?

J

[weaknessforcats]

Yes.

Then you can tackle how you remove a book from the array.

That may cause you to rehtink using a vector<book>.

[Hypnotik]

I actually do not have to remove any books from the array. Basically all I have to do is add books, decide whether the shelf is full, and display the books and info that begin with a specified letter.


I for some reason am unable to get out of my menu that prints out in main. When I remove the input function call, it exits. I've stared at the function for awhile and I can't see the problem.

 
#include <iostream>
#include <ctype.h>
using namespace std;
struct book
{
    char title[25],author[25];
    int ISBN,pages,year;
};
class shelf
{
private:
    book books[50];
    int num_books;
public:
    shelf();
    ~shelf(){};
    void input();
    void output();
    char alpha[2];
    bool full();
};
shelf::shelf()
{
    int i=0;
    cout<<"constructing our shelves"<<endl;
    for(i=0;i<25;++i)
    {
        books[i].title[i]='-';
        books[i].author[i]='-';
        books[i].ISBN=0;
        books[i].pages=0;
        books[i].year=0000;
    }
 
    for (i=0;i<2;++i)
    {
        alpha[i]='-';
    }
    num_books=0;
};
bool shelf::full()
{
    return (num_books==50);
}
void shelf::input()
{
    int sel=0,i=0;
    cout<<"This function allows the input of information for books."<<endl;
    cout<<"What would you like to enter?"<<endl;
    do
    {
        cout<<"1) Enter authors name."<<endl<<"2) Enter the title of the book."<<endl<<"3) Enter the ISBN."<<endl<<"4) Enter the number of pages."<<endl;
        cout<<"5) Enter the year the book was published."<<endl<<"6) Enter all of the information."<<endl<<"7) Exit"<<endl;
        cin>>sel;
        switch(sel)
        {
        case 1:
            cout<<"Enter the authors name."<<endl;
            cin.getline(books[i].author,20,'/n');
            cin.ignore();
            break;
        case 2:
            cout<<"Enter the title of the book."<<endl;
            cin.getline (books[i].title,20,'/n');
            cin.ignore();
            break;
        case 3:
            cout<<"Enter the ISBN of the book."<<endl;
            cin>>books[i].ISBN;
            break;
        case 4:
            cout<<"Enter the number of pages."<<endl;
            cin>>books[i].pages;
            break;
        case 5:
            cout<<"Enter the year the book was published."<<endl;
            cin>>books[i].year;
            break;
        case 6:
            cout<<"Enter the authors name."<<endl;
            cin.ignore();
            cin.getline(books[i].author,30,'\n');
            cout<<books[i].author<<endl;                                    
            cout<<"Enter the title of the book."<<endl;
            cin.getline (books[i].title,30,'\n');
            cout<<books[i].title<<endl;                                        
            cout<<"Enter the ISBN of the book."<<endl;
            cin>>books[i].ISBN;
            cout<<books[i].ISBN<<endl;
            cout<<"Enter the number of pages."<<endl;
            cin>>books[i].pages;
            cout<<books[i].pages<<endl;
            cout<<"Enter the year the book was published."<<endl;
            cin>>books[i].year;
            cout<<books[i].year<<endl;
            break;
        case 7:
            cout<<"Exiting."<<endl;
            break;
        default:
            cout<<"Make a selection from the menu."<<endl;
            break;
        }
    }
    while (sel<1||sel>7);
 
}
void shelf::output()
{
    int i=0;
    char let;
    cout<<"Enter the letter for which you would like to display titles: "<<endl;
    cin>>let;
    let=toupper(let);
    if (books[i].title[i]==let)
    {
        cout<<"Author        Title        ISBN        #Pages        Published"<<endl;
        cout<<books[i].author<<"     "<<books[i].title<<"     "<<books[i].ISBN<<"     "<<books[i].pages<<"     "<<books[i].year<<endl;
    }
    else
        cout<<"No book titles found which begin with the letter "<<let<<endl;
}
void main()
{
    char ans;
    int i=0;
    shelf library[25];
    do
    {
        cout<<"Do you have a book to enter? Enter Y for yes or N for no."<<endl;
        cin>>ans;
        ans=toupper(ans);
        cout<<ans<<endl;
    //    library[i].input();
        library[i].output();
    }
    while (ans=='Y');
    cout<<"Exiting program."<<endl;
}
 
 

Thanks,
J

[weaknessforcats]

case 7:
cout<<"Exiting. "<<endl;
break;
default:
cout<<"Make a selection from the menu."<<endl;
break;
}
}
while (sel<1||sel>7);

The exit is a 7. At 7 you break out of the switch. But you don't break out of the while until you enter a number > 7. Maybe you need:

while (sel != 7)

instead.

[Hypnotik]

The exit is a 7. At 7 you break out of the switch. But you don't break out of the while until you enter a number > 7. Maybe you need:

while (sel != 7)

instead.

The menu in the main program is what I can't exit out of if there is an input function call:

 
void main()
{
    char ans;
    int i=0;
    shelf library[25];
    do
    {
        cout<<"Do you have a book to enter? Enter Y for yes or N for no."<<endl;
        cin>>ans;
        ans=toupper(ans);
        cout<<ans<<endl;
        library[i].input();                        // if this is removed I can exit with ans=n
        library[i].output();
    }
    while (ans=='Y');
    cout<<"Exiting program."<<endl;
}
 
 

Thanks,
J

[weaknessforcats]

When the user enters N that means no more shelves are to be entered. So don't call shelf::input():

;
    do
    {
        cout<<"Do you have a book to enter? Enter Y for yes or N for no."<<endl;
        cin>>ans;
        ans=toupper(ans);
        cout<<ans<<endl;
        if (ans == 'Y')
        {
                library[i].input();      
                library[i].output();
         }
    }
    while (ans=='Y');
    cout<<"Exiting program."<<endl;
}
 
 
 

[Hypnotik]

Ugh....my brain is fried. Ofcourse I don't want to enter any info....if I don't have a book.

I appreciate it, my instructor is out of town and I'm working on 4 programs at the same time.

Thanks again, I'm sure I'll be posting more in this thread.

Jeff

[weaknessforcats]

I recommend a new thread. This one's about done.