C ++ - pointer release has not been allocated

Question

malloc: *** error for object 0x10ee008c0: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug Abort trap: 6 

Or I get it when I try to print everything

 Segmentation fault: 11 

I'm doing my homework for the OOP class, and now I'm stuck in a good hour. I get this error as soon as I used the keyboard enough. I am not the one who is upset at all, and here I am very upset by this. Here are the files:

This is a class book. I am sure it is very respectable. But for reference only:

 //--------------- BOOK.CPP --------------- // The class definition for Book. // #include <iostream> #include "book.h" using namespace std; Book::Book() // { strcpy(title, " "); strcpy(author, " "); type = FICTION; price = 0; } void Book::Set(const char* t, const char* a, Genre g, double p) { strcpy(title, t); strcpy(author, a); type = g; price = p; } const char* Book::GetTitle() const { return title; } const char* Book::GetAuthor() const { return author; } double Book::GetPrice() const { return price; } Genre Book::GetGenre() const { return type; } void Book::Display() const { int i; cout << GetTitle(); for (i = strlen(title) + 1; i < 32; i++) cout << (' '); cout << GetAuthor(); for (i = strlen(author) + 1; i < 22; i++) cout << (' '); switch (GetGenre()) { case FICTION: cout << "Fiction "; break; case MYSTERY: cout << "Mystery "; break; case SCIFI: cout << "SciFi "; break; case COMPUTER: cout << "Computer "; break; } cout << "$"; if (GetPrice() < 1000) cout << " "; if (GetPrice() < 100) cout << " "; if (GetPrice() < 10) cout << " "; /* printf("%.2f", GetPrice());*/ cout << '\n'; } 

This is a storage class that deals with array and dynamic allocation. This worked well without input commands, but just using its functions, it worked like a champion.

 //--------------- STORE.CPP --------------- // The class definition for Store. // #include <iostream> #include <cstring> // for strcmp #include "store.h" using namespace std; Store::Store() { maxSize = 5; currentSize = 0; bookList = new Book[maxSize]; } Store::~Store() // This destructor function for class Store // deallocates the Store list of Books { delete [] bookList; } void Store::Insert(const char* t, const char* a, Genre g, double p) // Insert a new entry into the direrctory. { if (currentSize == maxSize)// If the directory is full, grow it. Grow(); bookList[currentSize++].Set(t, a, g, p); } void Store::Sell(const char* t) // Sell a book from the store. { char name[31]; strcpy(name, t); int thisEntry = FindBook(name);// Locate the name in the directory. if (thisEntry == -1) cout << *name << " not found in directory"; else { cashRegister = cashRegister + bookList[thisEntry].GetPrice(); // Shift each succeding element "down" one position in the // Entry array, thereby deleting the desired entry. for (int j = thisEntry + 1; j < currentSize; j++) bookList[j - 1] = bookList[j]; currentSize--;// Decrement the current number of entries. cout << "Entry removed.\n"; if (currentSize < maxSize - 5)// If the directory is too big, shrink it. Shrink(); } } void Store::Find(const char* x) const // Display the Store matches for a title or author. { // Prompt the user for a name to be looked up char name[31]; strcpy(name, x); int thisBook = FindBook(name); if (thisBook != -1) bookList[thisBook].Display(); int thisAuthor = FindAuthor(name, true); if ((thisBook == -1) && (thisAuthor == -1)) cout << name << " not found in current directory\n"; } void Store::DisplayGenre(const Genre g) const { double genrePrice = 0; int genreCount = 0; for (int i = 0; i < currentSize; i++)// Look at each entry. { if (bookList[i].GetGenre() == g) { bookList[i].Display(); genrePrice = genrePrice + bookList[i].GetPrice(); genreCount++; } } cout << "Number of books in this genre: " << genreCount << " " << "Total: $"; if (genrePrice < 1000) cout << " "; if (genrePrice < 100) cout << " "; if (genrePrice < 10) cout << " "; printf("%.2f", genrePrice); } void Store::DisplayStore() const { if (currentSize >= 1) { cout << "**Title**\t\t" << "**Author**\t" << "**Genre**\t" << "**Price**\n\n"; for (int i = 0; i < currentSize; i++) bookList[i].Display(); } else cout << "No books currently in inventory\n\n"; cout << "Total Books = " << currentSize << "\nMoney in the register = $"; if (cashRegister < 1000) cout << " "; if (cashRegister < 100) cout << " "; if (cashRegister < 10) cout << " "; printf("%.2f", cashRegister); cout << '\n'; } void Store::Sort(char type) { Book temp; for(int i = 0; i <= currentSize; i++) { for (int j = i+1; j < currentSize; j++) { if (type == 'A') { if (strcmp(bookList[i].GetTitle(), bookList[j].GetTitle()) > 0) { temp = bookList[i]; bookList[i] = bookList[j]; bookList[j] = temp; } } if (type == 'T') { if (strcmp(bookList[i].GetAuthor(), bookList[j].GetAuthor()) > 0) { temp = bookList[i]; bookList[i] = bookList[j]; bookList[j] = temp; } } } } } void Store::SetCashRegister(double x) // Set value of cash register { cashRegister = x; } void Store::Grow() // Double the size of the Store bookList // by creating a new, larger array of books // and changing the store pointer to refer to // this new array. { maxSize = currentSize + 5;// Determine a new size. cout << "** Array being resized to " << maxSize << " allocated slots" << '\n'; Book* newList = new Book[maxSize];// Allocate a new array. for (int i = 0; i < currentSize; i++)// Copy each entry into newList[i] = bookList[i];// the new array. delete [] bookList;// Remove the old array bookList = newList;// Point old name to new array. } void Store::Shrink() // Divide the size of the Store bookList in // half by creating a new, smaller array of books // and changing the store pointer to refer to // this new array. { maxSize = maxSize - 5;// Determine a new size. cout << "** Array being resized to " << maxSize << " allocated slots" << '\n'; Book* newList = new Book[maxSize];// Allocate a new array. for (int i = 0; i < currentSize; i++)// Copy each entry into newList[i] = bookList[i];// the new array. delete [] bookList;// Remove the old array bookList = newList;// Point old name to new array. } int Store::FindBook(char* name) const // Locate a name in the directory. Returns the // position of the entry list as an integer if found. // and returns -1 if the entry is not found in the directory. { for (int i = 0; i < currentSize; i++)// Look at each entry. if (strcmp(bookList[i].GetTitle(), name) == 0) return i;// If found, return position and exit. return -1;// Return -1 if never found. } int Store::FindAuthor(char* name, const bool print) const // Locate a name in the directory. Returns the // position of the entry list as an integer if found. // and returns -1 if the entry is not found in the directory. { int returnValue; for (int i = 0; i < currentSize; i++)// Look at each entry. if (strcmp(bookList[i].GetAuthor(), name) == 0) { if (print == true) bookList[i].Display(); returnValue = i;// If found, return position and exit. } else returnValue = -1;// Return -1 if never found. return returnValue; } 

Now this is the guy who needs some work. Some things may be empty, so ignore this. It controls all the input that I consider.

 #include <iostream> #include "store.h" using namespace std; void ShowMenu() // Display the main program menu. { cout << "\n\t\t*** BOOKSTORE MENU ***"; cout << "\n\tA \tAdd a Book to Inventory"; cout << "\n\tF \tFind a book from Inventory"; cout << "\n\tS \tSell a book"; cout << "\n\tD \tDisplay the inventory list"; cout << "\n\tG \tGenre summary"; cout << "\n\tO \tSort inventory list"; cout << "\n\tM \tShow this Menu"; cout << "\n\tX \teXit Program"; } char GetAChar(const char* promptString) // Prompt the user and get a single character, // discarding the Return character. // Used in GetCommand. { char response;// the char to be returned cout << promptString;// Prompt the user cin >> response;// Get a char, response = toupper(response);// and convert it to uppercase cin.get();// Discard newline char from input. return response; } char Legal(char c) // Determine if a particular character, c, corresponds // to a legal menu command. Returns 1 if legal, 0 if not. // Used in GetCommand. { return((c == 'A') || (c == 'F') || (c == 'S') || (c == 'D') || (c == 'G') || (c == 'O') || (c == 'M') || (c == 'X')); } char GetCommand() // Prompts the user for a menu command until a legal // command character is entered. Return the command character. // Calls GetAChar, Legal, ShowMenu. { char cmd = GetAChar("\n\n>");// Get a command character. while (!Legal(cmd))// As long as it not a legal command, {// display menu and try again. cout << "\nIllegal command, please try again . . ."; ShowMenu(); cmd = GetAChar("\n\n>"); } return cmd; } void Add(Store s) { char aTitle[31]; char aAuthor[21]; Genre aGenre = FICTION; double aPrice = 10.00; cout << "Enter title: "; cin.getline(aTitle, 30); cout << "Enter author: "; cin.getline(aAuthor, 20); /* cout << aTitle << " " << aAuthor << "\n"; cout << aGenre << " " << aPrice << '\n'; */ s.Insert(aTitle, aAuthor, aGenre, aPrice); } void Find() { } void Sell() { } void ViewGenre(Store s) { char c; Genre result; do c = GetAChar("Enter Genre - (F)iction, (M)ystery, (S)ci-Fi, or (C)omputer: "); while ((c != 'F') && (c != 'M') && (c != 'S') && (c != 'C')); switch (result) { case 'F': s.DisplayGenre(FICTION); break; case 'M': s.DisplayGenre(MYSTERY); break; case 'S': s.DisplayGenre(SCIFI); break; case 'C': s.DisplayGenre(COMPUTER); break; } } void Sort(Store s) { char c; Genre result; do c = GetAChar("Enter Genre - (F)iction, (M)ystery, (S)ci-Fi, or (C)omputer: "); while ((c != 'A') && (c != 'T')); s.Sort(c); } void Intro(Store s) { double amount; cout << "*** Welcome to Bookstore Inventory Manager ***\n" << "Please input the starting money in the cash register: "; /* cin >> amount; s.SetCashRegister(amount);*/ } int main() { Store mainStore;// Create and initialize a Store. Intro(mainStore);//Display intro & set Cash Regsiter ShowMenu();// Display the menu. /*mainStore.Insert("A Clockwork Orange", "Anthony Burgess", SCIFI, 30.25); mainStore.Insert("X-Factor", "Anthony Burgess", SCIFI, 30.25);*/ char command;// menu command entered by user do { command = GetCommand();// Retrieve a command. switch (command) { case 'A': Add(mainStore); break; case 'F': Find(); break; case 'S': Sell(); break; case 'D': mainStore.DisplayStore(); break; case 'G': ViewGenre(mainStore); break; case 'O': Sort(mainStore); break; case 'M': ShowMenu(); break; case 'X': break; } } while ((command != 'X')); return 0; } 

Please, any help you can offer is awesome. Thanks.

Answer 1

Welcome to the exciting world of C ++!

Short answer: you pass the Store as a value. All your menu functions must accept Store & or Save *.

When you pass the Store as a value, then an implicit copy is executed (so the mainStore variable never changes). When you return from a function, Store :: ~ Store is called to clear the copied data. This frees up mainStore.bookList without changing the actual value of the pointer.

Further manipulation of the menu will ruin the memory and make many double releases.

TIP. If you are running Linux, you can run your program under valgrind, and this will indicate the simplest memory errors.

Answer 2

Your Store contains dynamically allocated data but does not have an assignment operator. You have violated rule three.

Answer 3

I don’t see the Store class being created somewhere by calling new Store() , which means that the booklist array was not created, but when the program exits and calls the destructor, it tries to remove the array that was never allocated and therefore why I think you get this error. Either change the destructor to a null check, or create an instance of the class by calling the constructor. Your code should not work wherever you try to use the Store object.

Hope this helps