C++程序執行對象功能時崩潰

Question

下面是代碼的一部分：

class Inventory { 
    public: 
     void PrintInventory(); 
     void AddItemToInventory(); 
     void UpdateItemQtyInInventory(); 
     void RemoveItemFromInventory(); 
    private: 
     vector<Item*> inventory; 
}; 

void Inventory::PrintInventory() { 
    unsigned int i = 0; 
    if (inventory.size() == 0) { 
     cout << "No items to print." << endl; 
    } else { 
     for (i=0; i < inventory.size(); ++i) { 
      cout << i << " - "; 
      inventory.at(i)->Print(); 
     } 
    } 
    return; 
} 

void Inventory::AddItemToInventory() { 
    string usrInptName = ""; 
    string usrInptQntyStr = ""; 
    string usrInptPriceStr = ""; 
    string usrInptOptn = "default"; 
    istringstream inSS; 
    int usrInptQnty = 0; 
    int usrInptPrice = 0; 
    string usrInptOther = ""; 
    bool valid = false; 

    while (valid == false) { 
     cout << "Enter (b)ook or (p)roduce: "; 
     getline(cin, usrInptOptn); 

     if (usrInptOptn.size() == 0) { 
       continue; 
     } else if (usrInptOptn.at(0) == 'p') { 
      Produce* prdct; 

      cout << "Enter name of new produce: "; 
      getline(cin, usrInptName); 

      cout << "Enter the price per item: $"; 
      getline(cin, usrInptPriceStr); 
      inSS.str(usrInptPriceStr); 
      inSS >> usrInptPrice; 
      inSS.clear(); 

      cout << "Enter quantity: "; 
      getline(cin, usrInptQntyStr); 
      inSS.str(usrInptQntyStr); 
      inSS >> usrInptQnty; 
      inSS.clear(); 

      cout << "Enter expiration date: "; 
      getline(cin, usrInptOther); 

      prdct = new Produce; 
      prdct->SetName(usrInptName); 
      prdct->SetPrice(usrInptPrice); 
      prdct->SetQuantity(usrInptQnty); 
      prdct->SetExpiration(usrInptOther); 

      inventory.push_back(prdct); 
      valid = true; 

     } else if (usrInptOptn.at(0) == 'b') { 
      Book* prdct; 

      cout << "Enter name of new book: "; 
      getline(cin, usrInptName); 

      cout << "Enter the price per item: $"; 
      getline(cin, usrInptPriceStr); 
      inSS.str(usrInptPriceStr); 
      inSS >> usrInptPrice; 
      inSS.clear(); 

      cout << "Enter quantity: "; 
      getline(cin, usrInptQntyStr); 
      inSS.str(usrInptQntyStr); 
      inSS >> usrInptQnty; 
      inSS.clear(); 

      cout << "Enter Author: "; 
      getline(cin, usrInptOther); 

      prdct = new Book; 
      prdct->SetName(usrInptName); 
      prdct->SetPrice(usrInptPrice); 
      prdct->SetQuantity(usrInptQnty); 
      prdct->SetAuthor(usrInptOther); 

      inventory.push_back(prdct); 
      valid = true; 
     } else { 
      cout << "Invalid choice\n"; 
     } 

    } 

    return; 
} 

Inventory* inventory; 

int main() { 
    string usrInptOptn = "default"; 

    while (true) { 
     // Get user choice 
     cout << "\nEnter (p)rint, (a)dd, (u)pdate, (r)emove, or (q)uit: "; 
     getline(cin, usrInptOptn); 

     // Process user choice 
     if (usrInptOptn.size() == 0) { 
      continue; 
     } else if (usrInptOptn.at(0) == 'p') { 
      inventory->PrintInventory(); 
     } else if (usrInptOptn.at(0) == 'a') { 
      inventory->AddItemToInventory(); 
     } else if (usrInptOptn.at(0) == 'u') { 
      inventory->UpdateItemQtyInInventory(); 
     } else if (usrInptOptn.at(0) == 'r') { 
      inventory->RemoveItemFromInventory(); 
     } else if (usrInptOptn.at(0) == 'q') { 
      cout << "\nGood bye." << endl; 
      break; 
     } 

    } 

    return 0; 
} 

當它正在運行的功能的程序崩潰。我沒有絲毫的想法。 AddItemtoIventory函數在程序崩潰之前全部運行，而另一個和其他程序崩潰。

Answer 1

這裏你不需要全局變量。只需在主範圍內創建一個清單對象

int main() { 
    Inventory inv; 
    // Rest of your code below 

    return 0; 
} 

或者，您也可以使用指針並使用新指針。

int main() { 
    Inventory* inv = new Inventory; 
    // Rest of your code below 

    return 0; 
}