erreur ambiguë: modèle C++

Question

J'ai essayé presque tout ce qui est imaginable (en dehors de la bonne chose bien sûr), mais je ne vois toujours pas pourquoi je reçois une erreur ambiguë. Je suis à peu près certain que c'est quelque chose de vraiment idiot mais je ne peux pas le voir! Mon compilateur montre des avertissements avec les opérateurs d'insertion et je sais qu'ils s'appellent tous les deux mais on m'a dit que coller dans le vieux virtual m'aiderait là-bas (et il n'a pas ...), pas encore de toute façon!

#include<iostream> 
#include<iomanip> 
#include<vector> 
#include<string> 
#include<algorithm> 
using namespace std; 

template <class T> 
T produceReport(string title, T accType, int tableRows) 
{ 
    cout << title << endl; 
    for (int x = 0; x < tableRows; x++) 
    { 
     cout << "-"; 
    } 
    cout << endl << accType; 
}; 

class BankAccount 
{ 
private: 
    int accNum; 
    double accBal; 
public: 
    BankAccount(int = 0, double = 0.0); 
    void enterAccountData(); 
    void displayAccount(); 
}; 

BankAccount::BankAccount(int num, double bal) 
{ 
    accNum = num; 
    accBal = bal; 
} 

void BankAccount::enterAccountData() 
{ 
    cout << setprecision(2) << fixed; 

    const int MIN_ACC = 1000, MAX_ACC = 9999, DEFAULT = 0; 

    cout << "Enter account number: "; 
    cin >> accNum; 

    if (accNum < MIN_ACC || accNum > MAX_ACC) 
     accNum = DEFAULT; 

    cout << "Enter account balance: $"; 
    cin >> accBal; 
} 

void BankAccount::displayAccount() 
{ 
    cout << "Account#" << accNum << 
     ", Balance: $" << accBal << endl; 
} 

class SavingsAccount: virtual public BankAccount 
{ 
    friend ostream& operator<<(ostream&, SavingsAccount); 
protected: 
    double intRate; 
public: 
    SavingsAccount(double = 0.0); 
    void getSavAccount(); 
    void displayAccount(); 
}; 

SavingsAccount::SavingsAccount(double rate) 
{ 
    intRate = rate; 
} 

void SavingsAccount::getSavAccount() 
{ 
    cout << "Enter interest rate: "; 
    cin >> intRate; 
} 

ostream& operator<<(ostream& out, SavingsAccount savAcc) 
{ 
    savAcc.displayAccount(); 
    return out; 
} 

void SavingsAccount::displayAccount() 
{ 
    BankAccount::displayAccount(); 
    cout << "Interest rate is: " << intRate << endl; 
} 

class CheckingAccount: virtual public BankAccount 
{ 
    friend ostream& operator<<(ostream&, CheckingAccount); 
private: 
    double monthFee; 
    int numChecks; 
public: 
    CheckingAccount(int = 0, double = 0.0, double = 0.0, int = 0); 
    void getCheckAccount(); 
    void displayAccount(); 
}; 

CheckingAccount::CheckingAccount(int num, double bal, double fee, int check): 
BankAccount(num, bal), monthFee(fee), numChecks(check) 
{} 

void CheckingAccount::getCheckAccount() 
{ 
    cout << "Enter monthly fee for account: $"; 
    cin >> monthFee; 
    cout << "Enter number of checks remaining: "; 
    cin >> numChecks; 
} 

ostream& operator<<(ostream& out, CheckingAccount checkAcc) 
{ 
    checkAcc.displayAccount(); 
    return out; 
} 

void CheckingAccount::displayAccount() 
{ 
    BankAccount::displayAccount(); 
    cout << "Monthly fee on account is: $" << monthFee << endl; 
    cout << "Checks remaining for account: " << numChecks << endl << endl; 
} 

class CheckingAccountWithInterest: public SavingsAccount, public CheckingAccount 
{ 
public: 
    CheckingAccountWithInterest(); 
    void displayAccount(); 
}; 

CheckingAccountWithInterest::CheckingAccountWithInterest(): 
CheckingAccount(), SavingsAccount() 
{} 

void CheckingAccountWithInterest::displayAccount() 
{ 
    BankAccount::displayAccount(); 
    intRate = 0.02; 
    SavingsAccount::displayAccount(); 
    CheckingAccount::displayAccount(); 
} 

int main() 
{ 
    const int NUM_ACCS = 5; 
    unsigned count; 
    vector<SavingsAccount> savAcc; 
    SavingsAccount aSavAcc; 
    vector<CheckingAccount> checkAcc; 
    CheckingAccount aCheckAcc; 
    vector<CheckingAccountWithInterest> checkAccWithInt; 
    CheckingAccountWithInterest aCheckAccWithInt; 

    for (count = 0; count < NUM_ACCS; count++) 
    { 
     aSavAcc.enterAccountData(); 
     aSavAcc.getSavAccount(); 
     savAcc.push_back(aSavAcc); 
    } 
    for (count = 0; count < NUM_ACCS; count++) 
    { 
     aCheckAcc.enterAccountData(); 
     aCheckAcc.getCheckAccount(); 
     checkAcc.push_back(aCheckAcc); 
    } 
    for (count = 0; count < NUM_ACCS; count++) 
    { 
     aCheckAccWithInt.enterAccountData(); 
     aCheckAccWithInt.getSavAccount(); 
     aCheckAccWithInt.getCheckAccount(); 
     checkAccWithInt.push_back(aCheckAccWithInt); 
    } 
    cout << endl; 
    for (count = 0; count < NUM_ACCS; count++) 
    { 
     produceReport("Savings Account Information", savAcc.at(count), 25); 
    } 
    for (count = 0; count < NUM_ACCS; count++) 
    { 
     produceReport("Checking Account Information", checkAcc.at(count), 25); 
    } 
    for (count = 0; count < NUM_ACCS; count++) 
    { 
     produceReport("Checking Account With Interest Information", checkAccWithInt.at(count), 30); 
    } 
} 

Erreur lors de l'appel est cout << endl << accType;

template <class T> 
    T produceReport(string title, T accType, int tableRows) 
    { 
     cout << title << endl; 
     for (int x = 0; x < tableRows; x++) 
     { 
      cout << "-"; 
     } 
     cout << endl << accType; 
    }; 

ProduceReport.cpp:16: error: ambiguous overload for 'operator<<' in 'std::cout. std::basic_ostream<_CharT, _Traits>::operator<< [with _CharT = char, _Traits = std::char_traits<char>](std::endl [with _CharT = char, _Traits = std::char_traits<char>]) << accType'

est le message d'erreur.

Toute aide ou conseils sont grandement appréciés pour la façon de surmonter cette erreur!

Answer 1

CheckingAccountWithInterest hérite de deux classes. Tous les deux supportent un operator<< qui est également susceptible d'être celui que CheckingAccountWithInterest devrait utiliser. Peu importe qu'ils appellent tous les deux displayAccount(); l'ambiguïté se produit avant que le compilateur n'y arrive. Vous devez trier cette ambiguïté.