使用類和構造函數並創建一個數組大小爲3的對象名稱

Question

我試圖在三個數組中創建一個主對象。當我運行它時，它會顯示所需的輸出，但它會給出錯誤，並且之後的任何代碼都不會運行。 「Grocery.exe中0x775FC41F未處理的異常：Microsoft C++異常：內存位置0x0036E590處的std :: bad_alloc」。

class GroceryItem { 
    public: 
    GroceryItem();//default constructor 
    GroceryItem(string, double, int, int); // four argument constructor 
    void set_item_name(string); // Assigns a value to the data memeber item_name 
    void set_item_price(double); //Assigns a value to the data member item_price 
    void set_qty_on_hand(int);// Assigns a value to the data member quantity_on_hand. 
    void set_qty_purchased(int); // Sets qty_purchased to zero before a customer begins shopping. 
    string get_item_name(); // Returns the value of the data memebr item_name. 
    double get_item_price(); // Returns the value of the data member item_price 
    int get_qty_on_hand(); // Returns the value of the data member quantity_on_hand. 
    int get_qty_purchased(); // Retruns the value of the data memebr qty_purchased. 
    private: 
      string item_name; 
      double item_price; 
      int quantity_on_hand; 
      int quantity_purchased; 
    }; 

    GroceryItem::GroceryItem(string name, double price, int hand, int purchased){ 
    set_item_name(name); 
    set_item_price(price); 
    set_qty_on_hand(hand); 
    set_qty_purchased(purchased); 
    } 
    void GroceryItem::set_item_name(string name){ 
    item_name = name; 
    } 
    string GroceryItem::get_item_name(){ 
    return item_name; 
    } 
    void GroceryItem::set_item_price(double price){ 
    item_price = price; 
    } 
    double GroceryItem::get_item_price(){ 
    return item_price; 
    } 
    void GroceryItem::set_qty_on_hand(int hand){ 
    quantity_on_hand = hand; 
    } 
    int GroceryItem::get_qty_on_hand(){ 
    return quantity_on_hand; 
    } 
    void GroceryItem::set_qty_purchased(int purchased){ 
    if (purchased > 0) 
    quantity_purchased = purchased; 
    if (purchased <= 0) 
    { 
    quantity_purchased = 0; 
    cout <<"\n cart cannot be negative, it will be set to 0. \n"; 
    } 
    } 
    int GroceryItem::get_qty_purchased(){ 
    return quantity_purchased; 
    } 



int main(){ 
int input; 
cout <<"Welcome to KMART\n" << "\nHappy Shopping" << endl; 
GroceryItem Kmart("Hello", 1234, 1234, 1); 
GroceryItem Kmart2("My", 1234, 1234, 1); 
GroceryItem Kmart3[SIZE] = { 
    { "John", 1234, 1234, 0 }, 
    { "Mary", 1234, 1234, 0 }, 
    { "Kevin", 1234, 1234, 0 } 

}; 
//Kmart("jjj", 12, 123, 1); 
for (int i = 0; i < 10; i++){ 
cout << Kmart3[i].get_item_name() << "\t" << Kmart3[i].get_item_price() << "\t" <<     Kmart3[i].get_qty_on_hand() << "\t" << Kmart3[i].get_qty_purchased() << endl; 
} 
cout << "This is fromt eh four argument constructor" << endl; 
cout<<Kmart.get_item_name()<<"\t"<<Kmart.get_item_price()<<"\t"<<Kmart.get_qty_on_hand()<<"\t"<<Kmart.get_qty_purchased()<<endl; 
cout << Kmart2.get_item_name() << "\t" << Kmart2.get_item_price() << "\t" << Kmart2.get_qty_on_hand() << "\t" << Kmart2.get_qty_purchased() << endl; 

}

Answer 1

您還沒有與我們分享了大小的值;不過，我猜測你可能不到10個。如果是這樣的話，那麼當你通過Kmart3循環時，它會崩潰。

此更改應停止崩潰（至少它在我的測試中）：

for (int i = 0; i < SIZE; i++) 
{ 
    if (Kmart3[i].get_item_name().length() > 0) 
     cout << Kmart3[i].get_item_name().c_str() << "\t" << Kmart3[i].get_item_price() << "\t" << Kmart3[i].get_qty_on_hand() << "\t" << Kmart3[i].get_qty_purchased() << endl; 
} 

當然，也有你需要解決一些其他問題之前，代碼工作，因爲我認爲你的意思是它的工作;但是，這應該可以阻止崩潰。