引发异常时的编译器错误

Question

I am currently learning about exceptions handling, and here is part of my code:

//vector.cpp

#include "vector.h"

Vector::Vector(int s)
{
    if (s < 0) throw length_error{};
    elem = new double[s];
    sz = s;
}

here is the code I am trying to test the exception by:

try{
    Vector v(-27);
}
catch (length_error)
{
    cout << "There was a negative size for your vector.\n";
}
catch (bad_alloc)
{
    cout << "The memory was not allocated properly.\n";
}

When I try to run my application, I get the following error:

error C2440: '<function-style-cast>' : cannot convert from 'initializer-list' to 'std::length_error'

Where is the error?

EDIT: The code was copied from C++ Programming Language Book .

Answer 1

According to cppreference.com std::length_error has the two constructors:

explicit length_error( const std::string& what_arg );
explicit length_error( const char* what_arg );

And you are trying to construct with an empty parameters list. You need to pass in a string to the constructor.