Question

所以我试图创建一个bankaccount程序，它实际上将使用从一个名为statistics（statistics.cpp / statistics.h）的单独.cpp / .h程序派生的两个单独的类。我已经包含了标题在适当的位置内的文件，并确保我没有做出任何区分大小写的错误。向前进。我遇到的问题是我收到了错误 - ＆＃34;警告：未使用的变量＆＃39;提款＆＃39;未设定。＆＃34; - ＆＃34;警告：未使用的变量＆＃39;存款＆＃39;未设置。＆＃34;

我在statistics.cpp中正确地创建了构造函数/重载构造函数

 Statistics::Statistics(){
    size = 0;
    pData = nullptr;
    capacity = 0;
}


Statistics::Statistics(int capacity){
    pData = new double [capacity];
    size = 0;
    //int i = 0;
}

以及在我的statistics.h文件中定义它

class Statistics{
public:
    Statistics();//default constructor
    Statistics(int capacity);//...

在我的bankaccount.h文件中，我添加/创建了两个单独的类，以尝试开发聚合关系。

 //....
 private:
    double amount = 0;
    int transactions = 0;
    double value = 0;
    Statistics* deposits;
    Statistics* withdrawals;
 };
#endif

这就是我在bankaccount.cpp中初始化和设置类的方法

int main(){
   //Statistics aStatistics; Constructor of Statistics
   //aStatistics.test(); Test function for Statistics .cpp/.h files (Was 
   //successful)

   bankaccount abankaccount;
   abankaccount.test();
   return 0;
}

void bankaccount::test(){

    cout << "Hello, Welcome to Boca Regional Bank." << endl;
    cout << "**********************************************" << endl;
    cout << "What is the expected amount of transactions for this month?" 
    <<endl;
    cin>> transactions;
    Statistics withdrawals = Statistics(transactions); //"Warning: unused variable 'withdrawals'"
    Statistics deposits = Statistics(transactions); //"Warning: unused variable 'deposits'"
    int userchoice;
    do{
       cout << "\n";
       userchoice = getuseroption();
       process(userchoice,transactions);
    } while (userchoice != 0);
 }

    void bankaccount::process(int option, int transactions){
       switch (option){
        case 1:
           double temp1;
           cout <<endl;
           cout << "You've chosen to deposit into your Bank Account."
           << endl;
           cout << "Your current balance is " << amount << endl;
           cout << "How much would you like to deposit?" << endl;
           cin >> temp1;
           while ((temp1 < 0) || (temp1 > 100000) ){
                cout << "You've entered an invalid amount, please try 
                again."<<endl;
                cout << "How many would you like to deposit?"<<endl;
                cin >> temp1;
           }
         deposit(&amount,temp1);
         if (temp1 > 0){ 
           deposits->add(temp1); //Implementation of one of the functions 
                                 //from the statistics class
                                 //At this point the program crashes

           }
         else if (temp1 == 0){
           break;
           }
         break;
....}

这是Statistics .cpp / .h add（）;功能

void Statistics::add (double value){
    pData[size]=value;
    size++;
}

Answer 1

您好像要初始化deposits中withdrawals个实例的bankaccount和bankaccount::test()成员。但是，Statistics withdrawals = Statistics(transactions);只是创建一个局部变量并对其进行初始化。由于它从未使用过，编译器警告您可能打算做其他事情（比如初始化成员）。

你可能意味着：

withdrawals = new Statistics(transactions);
deposits = new Statistics(transactions);

如果这样做，则必须在delete析构函数中bankaccount这些对象，以避免内存泄漏。现代C ++提供了更好的方法来做到这一点，但这是非常不合适的。

注意：用户代码中的类名通常位于CamelCase，而不是alllowercase。

聚合关系 - 从单独的.cpp / .h初始化Private内的类

1 个答案: