错误：参数1

Question

我收到此错误信息与下面的代码中给出默认参数：

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

首先，我认为默认参数不允许作为在C++中的第一参数，但它是允许的。

Answer 1

您可能重新定义了函数实现中的默认参数。它只应在函数声明中定义。

//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){ 
}