錯誤：參數1

Question

我收到此錯誤信息與下面的代碼中給出默認參數：

class Money { 
public: 
    Money(float amount, int moneyType); 
    string asString(bool shortVersion=true); 
private: 
    float amount; 
    int moneyType; 
}; 

首先，我認爲默認參數不允許作爲在C++中的第一參數，但它是允許的。

Answer 1

您可能重新定義了函數實現中的默認參數。它只應在函數聲明中定義。

//bad (this won't compile) 
string Money::asString(bool shortVersion=true){ 
} 

//good (The default parameter is commented out, but you can remove it totally) 
string Money::asString(bool shortVersion /*=true*/){ 
} 

//also fine, but maybe less clear as the commented out default parameter is removed 
string Money::asString(bool shortVersion){ 
}