继承 C++ Qt 项目的问题

Question

我有一个 QT 项目，其中提供了 UML 图和一些说明（见下文）

我对自己在做什么一头雾水，所以我只想展示我所有的代码，它已经完成但没有工作......我现在遇到的主要错误是所有的构造函数交易类型（存款、取款和余额查询）给出 "no matching function for call to 'Transaction::Transaction()'" 错误。我可能只是做错了。感谢我能得到的任何帮助...

这是我的全部代码： savingsaccount.h

    #ifndef SAVINGSACCOUNT_H
    #define SAVINGSACCOUNT_H
    #include "transaction.h"
    #include "deposit.h"
    #include "balanceenquiry.h"
    #include "withdrawal.h"

    class SavingsAccount
    {
    private:
        QString m_CustomerName;
        QString m_AccountNumber;
        QList<Transaction*> m_TransactionList;
    public:
        SavingsAccount(QString name, QString num);
        ~SavingsAccount();
        void addTransaction(Transaction* t);
        double totalTransactionCost();
        QString frequentTransactionType();
        QList<Transaction*> transactionsOnAdate(QDate date);
        QString toString() const;
    };

    #endif // SAVINGSACCOUNT_H

savingsaccount.cpp

#include "savingsaccount.h"

SavingsAccount::SavingsAccount(QString name, QString num) {
    m_CustomerName = name;
    m_AccountNumber = num;
}
SavingsAccount::~SavingsAccount() {
    while(!m_TransactionList.isEmpty()) {
        delete m_TransactionList.takeFirst();
    } //Deletes all list items
}
SavingsAccount::addTransaction(Transaction* t) {
    m_TransactionList << t; //Adds transaction to list
}
double SavingsAccount::totalTransactionCost() {
    double totalCost;

    for(int i = 0; i < m_TransactionList.size(); i++) {
        totalCost += m_TransactionList.at(i)->computeCost();
    }

    return totalCost; //Returns total transaction cost
}
QString SavingsAccount::frequentTransactionType() {
    QString frequentType;
    int deposit, withdrawal, balanceEnquiry;

    for(int i = 0; i < m_TransactionList.size(); i++) {
        if(m_TransactionList.at(i)->getType() == "Deposit") {
            deposit++;
        }
        else if(m_TransactionList.at(i)->getType() == "Withdrawal") {
            withdrawal++;
        }
        else if(m_TransactionList.at(i)->getType() == "Balance Enquiry") {
            balanceEnquiry++;
        }
    }

    if(deposit > withdrawal && deposit > balanceEnquiry) {
        frequentType = "Deposit";
    } else if(withdrawal > balanceEnquiry && withdrawal > deposit) {
        frequentType = "Withdrawal";
    } else if(balanceEnquiry > deposit && balanceEnquiry > withdrawal) {
        frequentType = "Balance Enquiry";
    }
    else {
        frequentType = "NA";
    }

    return frequentType;//Returns most frequent transaction type
}
QList<Transactions*> SavingsAccount::transactionsOnDate(QDate date) {
    QList<Transaction*> transactions;

    for(int i = 0; i < m_TransactionList.size(); i++) {
        if(m_TransactionList.at(i)->getDateTime().date() == date) {
            transactions << m_TransactionList;
        }
    }

    return transactions;
}
QString SavingsAccount::toString() {
    return "Savings Account:\n================\n"
           + "Customer Name: " + m_CustomerName + "\n"
           + "Account Number: " + m_AccountNumber + "\n"
           + "================\nTransactions\n================\n"
           + m_TransactionList
           + "================\nTransaction Details\n================\n"
           + "Total Transaction Cost: R" + totalTransactionCost()
           + "Most Frequent Transaction Type: " + frequentTransactionType()
           + "================\nTransactions Today\n================"
           + transactionsOnAdate(QDate::currentDate());
}

transaction.h

#ifndef TRANSACTION_H
#define TRANSACTION_H
#include <QString>
#include <QDateTime>

class Transaction
{
protected:
    QString m_Type;
    QDateTime m_DateTime;
public:
    Transaction(QString type, QDateTime datetime);
    QString getType();
    QString toString();
    QDateTime getDateTime();
    virtual double computeCost();
};

transaction.cpp

#include "transaction.h"

Transaction::Transaction(QString type, QDateTime datetime) {
    m_Type = type;
    m_DateTime = datetime;
}
QString Transaction::getType() {
    return m_Type;
}
QString Transaction::toString() {
    return m_Type + " " + m_DateTime.toString() + "\n";
}
QDateTime Transaction::getDateTime() {
    return m_DateTime;
}
double Transaction::computeCost() {
    return 0;//Virtual Function (meant to be overrided)
}

deposit.h

#ifndef DEPOSIT_H
#define DEPOSIT_H
#include "transaction.h"
#include <QString>

class Deposit: public Transaction
{
private:
    double m_Amount;
    const double m_Fee = 5.0; //reasonable amount R5 deposit
public:
    Deposit(double amount);
    QString toString();
    double computeCost();
};

#endif // DEPOSIT_H

deposit.cpp

#include "deposit.h"

Deposit::Deposit(double amount) {
    m_Amount = amount;
    m_Type = "Deposit";
    m_DateTime = QDateTime::currentDateTime();
}
QString Deposit::toString() {
    return Transaction::toString() + "Amount: R" + m_Amount
            + "\nFee: R" + m_Fee;
}
double Deposit::computeCost() {
    return m_Fee;
}

withdrawal.h

#ifndef WITHDRAWAL_H
#define WITHDRAWAL_H
#include "transaction.h"
#include <QString>

class Withdrawal: public Transaction
{
private:
    double m_Amount;
    double m_Percentage = 3; //3% withdrawal cost
public:
    Withdrawal(double amount);
    QString toString() const;
    double computeCost();
};

#endif // WITHDRAWAL_H

withdrawal.cpp

#include "withdrawal.h"

Withdrawal::Withdrawal(double amount) {
    m_Amount = amount;
    m_Type = "Withdrawal";
    m_DateTime = QDateTime::currentDateTime();
}
QString Withdrawal::toString() {
    return Transaction::toString() + "Amount: R" + m_Amount
            + "\nFee Percentage: " + m_Percentage + "%";
}
double Withdrawal::computeCost() {
    return m_Amount*m_Percentage/100;
}

balanceenquiry.h

#ifndef BALANCEENQUIRY_H
#define BALANCEENQUIRY_H
#include "transaction.h"
#include <QString>
#include <QDate>

class BalanceEnquiry: public Transaction
{
private:
    QDate m_FromDate;
    QDate m_ToDate;
public:
    BalanceEnquiry(QDate fDate, QDate tDate);
    QString toString() const;
    double computeCost();
};

#endif // BALANCEENQUIRY_H

balanceenquiry.cpp

#include "balanceenquiry.h"

BalanceEnquiry::BalanceEnquiry(QDate fDate, QDate tDate) {
    m_FromDate = fDate;
    m_ToDate = tDate;
    m_Type = "Balance Enquiry";
    m_DateTime = QDateTime::currentDateTime();
}
QString BalanceEnquiry::toString() {
    return Transaction::toString() + "From: " + m_FromDate
            + "/nTo: " + m_ToDate;
}
double BalanceEnquiry::computeCost() {
    return 0; //Balance Enquiry costs nothing
}

main.cpp

#include <QCoreApplication>
#include "savingsaccount.h"
#include <QDebug>

QTextStream cout(stdout);

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    //Declare variables
    QString customerName = "Barry Doyle";
    QString accountNumber = "1234567890";

    //Implement Savings Account
    SavingsAccount account(customerName, accountNumber);

    //Implement Transactions
    Deposit d1(500.0);
    BalanceEnquiry b1(QDate::currentDate(), QDate::currentDate());
    Withdrawal w1(200.0);
    Withdrawal w2(250.0);
    BalanceEnquiry b2(QDate::currentDate(), QDate::currentDate());
    Deposit d2(400.0);
    Deposit d3(150.0);

    Transaction *t1 = &d1;
    Transaction *t2 = &b1;
    Transaction *t3 = &w1;
    Transaction *t4 = &w2;
    Transaction *t5 = &b2;
    Transaction *t6 = &d2;
    Transaction *t7 = &d3;

    //Add Transactions to Transaction List
    account.addTransaction(t1);
    account.addTransaction(t2);
    account.addTransaction(t3);
    account.addTransaction(t4);
    account.addTransaction(t5);
    account.addTransaction(t6);
    account.addTransaction(t7);

    account.toString();

    return a.exec();
}

Answer 1

例如：Deposit 来源于Transaction。存款构造函数隐式调用不带参数的事务构造函数 - Transaction()，但它不存在。因此，要解决您的问题，您应该定义不带参数的 Transaction 构造函数 - Transaction()，或者使用 2 个参数 Transaction(QString type, QDateTime datetime) 显式调用构造函数，如下所示：

Deposit::Deposit(double amount)
        : Transaction("Deposit", QDateTime::currentDateTime()) {
m_Amount = amount;
m_Type = "Deposit"; // this no need now
m_DateTime = QDateTime::currentDateTime(); // and this too

}

Answer 2

我认为对于 ua addTransaction 你应该使用像

这样的追加函数

void SavingsAccount::addTransaction(Transaction *t){
    m_TransactionList.append();

继承 C++ Qt 项目的问题

Issues with Inheritance C++ Qt Project

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qt

inheritance

base-class

qlist