Passing a string literal as a parameter to a C++ template class
You can have a const char*
non-type template parameter, and pass it a const char[]
variable with static
linkage, which is not all that far from passing a string literal directly.
#include <iostream>
template<const char *str>
struct cts {
void p() {std::cout << str;}
};
static const char teststr[] = "Hello world!";
int main() {
cts<teststr> o;
o.p();
}
http://coliru.stacked-crooked.com/a/64cd254136dd0272
Further from Neil's answer: one way to using strings with templates as you want is to define a traits class and define the string as a trait of the type.
#include <iostream>
template <class T>
struct MyTypeTraits
{
static const char* name;
};
template <class T>
const char* MyTypeTraits<T>::name = "Hello";
template <>
struct MyTypeTraits<int>
{
static const char* name;
};
const char* MyTypeTraits<int>::name = "Hello int";
template <class T>
class MyTemplateClass
{
public:
void print() {
std::cout << "My name is: " << MyTypeTraits<T>::name << std::endl;
}
};
int main()
{
MyTemplateClass<int>().print();
MyTemplateClass<char>().print();
}
prints
My name is: Hello int
My name is: Hello
Sorry, C++ does not currently support the use of string literals (or real literals) as template parameters.
But re-reading your question, is that what you are asking? You cannot say:
foo <"bar"> x;
but you can say
template <typename T>
struct foo {
foo( T t ) {}
};
foo <const char *> f( "bar" );