runtime_error expecting a “;”?

Question

I am trying to use inheritance to create a class derived from runtime_error , but I keep getting an error even though this is the exact code used in exercises and as an example from the book. Here is the code:

class DivideZeroEx : public runtime_error
{
    public:
        DivideZeroEx()
            runtime_error( " attempt to divide by zero" )
};

Now I get an error stating that it expects a ; before the runtime_error("attempt to divide by zero") line.

Answer 1

调用基类构造函数的语法应为：

DivideZeroEx() : runtime_error( " attempt to divide by zero" ) { }

Answer 2

You are trying to call the Base class constructor in Member Initializer List, the syntax is:

DivideZeroEx():runtime_error( " attempt to divide by zero" )
{
}

Answer 3

class DivideZeroEx : public runtime_error
{ 
public: 
   DivideZeroEx() : runtime_error( " attempt to divide by zero" ) 
   {
   }

};

Answer 4

In this instance it doesn't save much, but if you were to use runtime_error by name throughout your class, this is much easier to swap out the base in the future.

class DivideZeroEx : public runtime_error
{ 
typedef runtime_error base;

public: 
   DivideZeroEx() : base( " attempt to divide by zero" ) 
   {
   }
};