Question

I have the declared the following struct:

const struct DATABASE_ALREADY_EXISTS {
    const int Code = 2001;
    const char Str[] = "Database already exists.";
};

But then when I pass it to the function:

DATABASE_ALREADY_EXISTS DB_ERR;
error_output(DB_ERR.Str, DB_ERR.Code);

It throws the following error(Visual Studio 2013):

cannot specify explicit initializer for arrays

Here is the declaration error_output:

template<class D>
char* error_output(D err_str, int err_code = 0)
{
    return "(" + err_code + ") " + err_str;
}

How should I change the definition Str member of the struct to eliminate such error?

Answer 1

我认为你可以修改你的代码，如下所示;由于返回.video-container { position: relative; padding-bottom: 100%; height:100%; } .video-container iframe, .video-container object, .video-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; margin:0px; }没有任何意义，因此您无法在"(" + err_code + ") " + err_str;两个+上应用char *运算符。

#include <string>
#include <iostream>
#include <cstring>
#include <sstream>

struct DATABASE_ALREADY_EXISTS {
     DATABASE_ALREADY_EXISTS(const char* s) : Str(s) {}
     static const int Code = 2001;
     const char *Str;
};

template<class D>
const char* error_output(D err_str, int err_code = 0)
{
       std::istringstream is;
       is>>err_code;

       std::string str;
       str += "(";
       str += is.str();
       str += ") ";
       str += err_str;
       return str.c_str();
}

int main(void)
{
   DATABASE_ALREADY_EXISTS DB_ERR("Database already exists.");
   const char *res = error_output(DB_ERR.Str, DB_ERR.Code);
   std::cout<<res<<std::endl;
    return 0;
}

Answer 2

#include <iostream>
using namespace std;

struct Error {
private:
    static char Buf[1024];

public:
    int Code;
    char* Str;

    char* DisplayString() const  {
        sprintf_s(Buf, 1024, "(%d) %s", Code, Str);
        return Buf;
    }

    friend ostream& operator<<(ostream& os, const Error& rhs) {
        return os << rhs.DisplayString();
    }
};

char Error::Buf[1024];

#define DEC_ERROR(name, code, str) Error name = { code, str }

DEC_ERROR(DATABASE_ALREADY_EXISTS, 2001, "Database already exists.");
DEC_ERROR(UNICORN_WITHOUT_HORN, 2002, "Unicorns should have a horn.");

int _tmain(int argc, _TCHAR* argv[]) {
    cout << DATABASE_ALREADY_EXISTS << endl;
    cout << UNICORN_WITHOUT_HORN << endl;
}

输出：
（2001）数据库已经存在（2002）独角兽应该有一个角。

C++ error cannot specify explicit initializer for arrays for char g[]

2 个答案: