sirve - C++-el puntero liberado no fue asignado

getline c++

Question

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

O entiendo esto cuando intento imprimir todo

Segmentation fault: 11

Estoy haciendo algunos deberes para una clase OOP y he estado atrapado por una buena hora ahora. Recibo este error una vez que he usado suficiente entrada de teclado. No soy alguien que se frustre en absoluto, y aquí estoy muy frustrado con esto. Aquí están los archivos:

Esta es la clase de libro. Estoy bastante seguro de que esto es muy sólido. Pero solo para referencia:

//--------------- 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'';
}

Esta es la clase de tienda que trata con la matriz y la asignación dinámica. Esto funcionaba bien sin comandos de entrada, pero al usar sus funciones funcionaba como un campeón.

//--------------- 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''s 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''s 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''s bookList
// by creating a new, larger array of books
// and changing the store''s 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''s bookList in
// half by creating a new, smaller array of books
// and changing the store''s 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;
}

Ahora este es el tipo que necesita algo de trabajo. Puede haber algunas cosas en blanco, así que ignora eso. Este controla toda la entrada, que es el problema en el que creo.

#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''s 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;
}

Por favor, cualquier ayuda que puedas ofrecer es increíble. Gracias.

Answer 1

¡Bienvenido al apasionante mundo de C ++!

Respuesta corta: está pasando Store como un valor. Todas las funciones del menú deberían tener una tienda y / o tienda * en su lugar.

Cuando está pasando Store como valor, se realiza una copia implícita (por lo que la variable mainStore nunca se modifica). Cuando regrese de la función, se llama a Store :: ~ Store para limpiar los datos copiados. Esto libera mainStore.bookList sin cambiar el valor real del puntero.

La manipulación adicional del menú dañará la memoria y hará muchas dobleces libres.

SUGERENCIA: Si está en Linux, puede ejecutar su programa en valgrind y señalará la mayoría de los errores de memoria simples.

Answer 2

No veo la clase Store instanciada en ninguna parte mediante una llamada a new Store() que significa que la lista booklist no se ha creado, pero cuando el programa sale y llama al destructor, intenta eliminar la matriz que nunca se asignó y, por lo tanto, por eso creo que estás obteniendo este error. O bien, modifique el destructor para tener una comprobación nula o crear una instancia de la clase mediante una llamada al constructor. Su código no debería seguir funcionando en ningún lado que esté tratando de usar un objeto Store .

Espero que esto ayude

Answer 3

Su Store contiene datos asignados dinámicamente, pero no tiene un operador de asignación. Has violado la Regla de los Tres .