My application throws an exception most probably due to heap corruption as the error code given is c0000374.

It does this when creating the object at line :

Library library2("2");

My code:

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <string>
#include <fstream>
using namespace std;

class Book
{
private:
    char author[50];
    char bookid[10];
    char title[80];
public:
    Book(char* nid, char* ntitle, char* nauthor) {
        strcpy(author, nauthor);
        strcpy(title, ntitle);
        strcpy(bookid, nid);
    }
    Book() {
        strcpy(author, "\0");
        strcpy(title, "\0");
        strcpy(bookid, "\0");
    }
    
    void operator= (Book b) {
        strcpy(author, b.getAuthor());
        strcpy(title, b.getTitle());
        strcpy(bookid, b.getBookID());
    }
    
    friend ostream& operator<< (ostream& out, Book b) {
        out << b.title << "\t" << b.author << "\t" << b.bookid << endl;
        return out;
    }
    
    friend bool operator== (Book b1, Book b2) {
        return (strcmp(b1.bookid, b2.bookid));
    }
    
    char* getAuthor() {     return author;  }
    char* getBookID() {     return bookid;  }
    char* getTitle() {      return title;   }
};

class Library {
private:
    //libId: holds the library ID
    string libId;
    //Pointer to the array that holds the book objects
    Book* bookArr;
    //holds the number of books added in the array.
    int bookscount;
    
    void resizeBookArray(Book book) {
        bookscount  ;
        Book* newBookArr = new Book[bookscount];
        for (int i = 0; i < bookscount-1; i  )
        {
            newBookArr[i] = bookArr[i];
        }
        delete[] bookArr;
        bookArr = new Book[bookscount];
        newBookArr[bookscount] = book;
        bookArr = newBookArr;
        newBookArr = nullptr;
    }
public:
    
    Library(string alibId) {
        libId = alibId;
        bookscount = 0;
        bookArr = new Book[bookscount];
    }
    void operator= (Library lib) {
        bookscount = lib.getBookNum();
        copyBookArray(lib.getBookArr());
    }
    
    void addBook(Book book) {
        if (!search(book)) {
            resizeBookArray(book);
        }
    }
    
    bool search(Book book)
    {
        for (int i = 0; i < bookscount; i  )
        {
            if (bookArr[i] == book)
            {
                return true;
            }
        }
        return false;
    }
    
    friend ostream& operator<< (ostream& out, Library lib) {
        for (int i = 0; i < lib.bookscount; i  )
        {
            out << lib.bookArr[i];
        }
        return out;
    }
    string getID() { return libId; }
    int getBookNum() { return bookscount; }
    Book* getBookArr() { return bookArr; }

    void copyBookArray(Book* bArr) {
        delete[] bookArr;
        Book* bookArr = new Book[bookscount];
        for (int i = 0; i < bookscount; i  )
        {
            bookArr[i] = bArr[i];
        }
    }
};

void readBooksItems(Library& lib) {
    ifstream fin("book.txt");
    if (fin.fail()) cout << "Input file error!";
    char author[50];
    char bookid[10];
    char title[80];
    while (!fin.eof())
    {
        fin >> bookid;
        fin.ignore();
        fin.getline(title, 80);
        fin.getline(author, 50);
        Book btemp(bookid, title, author);
        lib.addBook(btemp);
    }
    fin.close();
}
//getMoreBooks function, gets additional book from the user, and adds the book into the array
Library getMoreBooks(Library lib)
{
    char bId[10], btitle[80], bauthor[50];
    cout << "Enter book id:";
    cin.getline(bId, 10);
    cout << "Enter title: ";
    cin.getline(btitle, 80);
    cout << "Enter author: ";
    cin.getline(bauthor, 50);
    Book b(bId, btitle, bauthor);
    lib.addBook(b);
    return lib;
}

int main()
{
    int numvideos, numbooks;
    Library library1("1");
    readBooksItems(library1);
    Library library2("2");
    library2 = library1;
    int nbooks;
    cout << "How many new books to add in library 1: ";
    cin >> nbooks;
    cin.ignore();
    for (int i = 0; i < nbooks; i  )
    {
        library1 = getMoreBooks(library1);
    }
    cout << "How many new books to add in library 2: ";
    cin >> nbooks;
    cin.ignore();
    for (int i = 0; i < nbooks; i  )
    {
        library2 = getMoreBooks(library2);
    }
    cout << "=======Printing all books in library 1========= " << endl;
    cout << library1;
    cout << "=======Printing all books in library 2========= " << endl;
    cout << library2;
    return 0;
}

Input file book.txt:

111
Cloud Computing
John Rapheal
222
Programming 1
Sam Smiths
333
UML 2 for Dummies
Michael Jesse Chonoles

CodePudding user response：

This line of code writes past the end of the array, which triggers undefined behavior.

        newBookArr[bookscount] = book;