Thread: Book Inventory (why not running?) help plz

hi,
my program of book inventory with no errors is giving errors at running time. plz check it , im writing algorithm also here:

Code:

ALGORITHM - BOOK INVENTORY PROGRAM C++

    create an inventory of books using constructor and destructor, the step by step algorithm is given below. 

  You have to create a class named “book” with  

  
  Attributes: string variable for author, title, and publisher and the integer variables for price and stock_position, successful_transaction, unsuccessful_transaction

  Functions:- 
  Ø  book(title, author, publishes, price and stock position) [stock position means number of books available] 
  Ø  buybook(title, author) [stock means number of  books user want to buy]
  Ø  transaction
  Ø  display.
  Ø  Int getStockPosition();
  Ø  ~book()
  
  
  Algorithm
  Step 1: Create an object for the class book.
  Step 2: Declare author, title, and publisher and the

  Variable for price and stock position.
  Step 3: create an array  of book objects and read 10 books from user i.e. create 10 books.

  Step 4: Display a menu with the following choices 
  Create books ,buybook, transaction and display.
  Step 5:Using switch case execute the statements corresponding to the choice.

  Step 6:If the choice is create, read the title, author, publishes, price and stock 

position and pass it to the constructor of the book class.
 
  

  Step 7:If the choice is buy books, read the title, author from the user and

  check these with the array already created.
  Step 8:If the author name and title matches and stock is available then display the message”:Available”

  Step 9:Decrement the stock position by 1 and display the mount to be paid.

  Note:- if after decrement stock position becomes zero, delete that object i.e. call destructor, and destructor should display the message that stock of the sold book [book title] is ended.
  Increment successful transaction by 1. Else display “NOT success” and increment the
  unsuccessful transaction by 1.
  Step 10:If the choice is  “transaction” then display the variables, successful transaction and

  unsuccessful transaction.
  Step 11:If the choice is “display”, then display all the details of the books such as title, author, price,

  publishes and stock position.

Code:

/////source or main cpp file


#include<iostream>
#include"book.h"
using namespace std;
void main()
{
system("COLOR 17");

book ob1;
ob1.Fmenu();


system("pause");

}

Code:

#pragma once
class book
{
/////book.h class file

private:

    char author[40],title[40], publisher[40];
    int price, stock_position, successful_transaction, unsuccessful_transaction,stock;
    int n;

public:
    
    int choice; ///variable
    void createBooks();
    book(char,char,char,int);
                                    ///book(title, author, publisher, price,stock position) 
    void buybook(char,char, int);
                                    ///buybook(title, author,stock)
    void transaction(int,book x[]);  ///flag, object
    void display(book x[]);  ////argument object of class
    int getStockPosition();

    void Fmenu();


    book(void);
    ~book(void);
};

Code:

////book.cpp ///cpp file of class

#include "book.h"
#include<iostream>
//////#include<string>
using namespace std;


book::book(void)
{
}

void book::Fmenu()
{
    char name[40],aname[40];
    int price;
cout<<"*****BOOK INVENTORY*****\n";
cout<<"1. Create Books\n2. Buy Books\n3. Transaction\n4. Display\n";
cout<<"Enter Choice: ";
cin>>choice;
switch(choice)
{
case 1:
    createBooks();
    break;
case 2:
    cout<<"\nEnter Book Name: ";
    cin>>name;
    cout<<"\nEnter Author Name: ";
    cin>>aname;
    cout<<"\nHow many books you want to buy? : ";
    cin>>price;
    buybook(name[40], aname[40], price);
    break;
case 3:
    book *ob2;
    transaction(0,&ob2[n]);
    break;
case 4:
    display(&ob2[n]);
    break;
}}

void book::createBooks()
{
cout<<"How many books you want to create?";
cin>>n;
book *ob2=new book[n];
for(int i=0; i<n; i++)
{
cout<<"Enter Book Name: ";
cin>>ob2[i].title;
cout<<"Enter Book Author: ";
cin>>ob2[i].author;
cout<<"Enter Book Publisher: ";
cin>>ob2[i].publisher;
cout<<"Enter Stock Position: ";
cin>>ob2[2].stock_position;
cout<<"Enter Book Price: ";
cin>>ob2[i].price;
cout<<"------------------\n\n";
}}

void book::buybook(char vtitle,char vauthor, int vstock)
{
    book *ob2;
    for(int i=0; i<10; i++)
    {
    if(vtitle==*ob2[i].title && vauthor==*ob2[i].author)
    {
    cout<<"\nAVAILABLE !\n";
    cout<<"Total Price: "<<vstock*(ob2[i].price);

    transaction(1,&ob2[n]);
    ob2[i].stock_position--;
    if(ob2[i].stock_position<=0)
      delete &ob2;

    }
    else transaction(2, &ob2[n]);
    }    
}

void book::transaction(int flag, book ob2[])
{
    //book *ob2;
    if(flag==1)
    {
    successful_transaction++;
    cout<<"\nSuccessful";
    }
    else if(flag==2)
    {
    for(int i=0; i<n; i++){
        cout<<"Books\tSuccessful Transaction\tUnsuccessful Transaction\n";
        cout<<"---------------------------------------------------------------------\n";
        cout<<ob2[i].title<<"\t"<<successful_transaction<<"\t"<<unsuccessful_transaction<<endl;
    }}

    else 
    {
    unsuccessful_transaction++;
    cout<<"\nNOT Success";
    }
}

void book::display(book ob2[])
{
    cout<<"\nTitle\tAuthor\tPrice\tPublisher\tStock Position\n";
    for(int i=0; i<n; i++)
        cout<<ob2[i].title<<"\t"<<ob2[i].author<<"\t"<<ob2[i].price<<"\t"<<ob2[i].publisher<<"\t"<<ob2[i].stock_position<<endl;    
}


book::~book(void)
{
    
    //cout<<"The stock of the sold book"<< ob2. << "is ended.";
    cout<<"\nThe stock of the sold book is ended.\n";
}

no one?

Also never use a function to retrieve a C-string that doesn't limit the number of characters it will receive. To safely use C-strings with cin you should #include the iomanip header file and use the setw() function to limit the number of characters to be retrieved.

Code:

char something[20];
cin >> setw(20) >> something;

Better yet stop using C-strings and start using std::strings.

Also beware that the extraction operator stops processing strings when it encounters a whitespace character, so if you really should be using getline() to retrieve strings of any kind.

You also need to use more descriptive variable names. For instance naming a variable "n" in your class can get very confusing when you go to use that variable. Single letter names should be limited to the closest possible scope. Plus I don't see where you are actually assigning a value to this variable, it also looks like it should be a const and initialized in your constructor.


Jim

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