C 样式字符串作为模板参数?

问题描述

C 样式字符串可以用作模板参数吗?

Can C-Style strings be used as template arguments?

我试过了:

template <char *str>
struct X
{
    const char *GetString() const
    {
         return str;
    }
};

int main()
{
    X<"String"> x;
    cout<<x.GetString();
}

虽然我没有收到关于类定义的抱怨，但实例化会产生 'X' : invalid expression as a template argument for 'str' (VC).

And although I get no complaints about the class definition, the instantiation yields 'X' : invalid expression as a template argument for 'str' (VC).

推荐答案

不能使用字符串文字作为模板参数.

更新:如今，在提出并回答这个问题几年后，可以使用字符串文字作为模板参数.使用 C++11，我们可以使用字符包作为模板参数 (template<char ...c>) 并且它 可以将文字字符串传递给这样的模板.

Update: Nowadays, a few years after this question was asked and answered, it is possible to use string literals as template arguments. With C++11, we can use characters packs as template arguments (template<char ...c>) and it is possible to pass a literal string to such a template.

这会奏效:

template <char const *str>
struct X
{
    const char *GetString() const
    {
         return str;
    }
};

char global_string[] = "String";

int main()
{
    X<global_string> x;
    cout<<x.GetString();
}

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