concatenate char * to string - c++

Question

I have a function which is expecting a string, I was wanting to concatenate const char * to a string to be returned.
Here is example code to help illustrate this scenario:
void TMain::SomeMethod(std::vector<std::string>* p)
{
p->push_back(TAnotherClass::Cchar1 + "/" + TAnotherClass::Cchar2);
}
and here is the other class these are from:
class TAnotherClass
{
public:
static const char * Cchar1;
static const char * Cchar2;
};
const char * TAnotherClass::Cchar1 = "Home";
const char * TAnotherClass::Cchar2 = "user";
im getting the following error:
invalid operands of types 'const char*' and 'const char*' to binary operator +
Why is this not valid? please help

Answer 1

char const* cannot be used with + operator, as the error says.
What you need to do is this:
p->push_back(std::string(TAnotherClass::Cchar1) + "/" + TAnotherClass::Cchar2);
//^^^^^^^^^^^^ notice this
It creates a temporary object of type std::string, then you can use + with it. It concatenates the strings, creating temporaries all the way, and finally passes the final string to push_back.
Apart from that, as #Konrad noted in the comment, don’t pass a pointer into the method, use a reference instead, as:
void TMain::SomeMethod(std::vector<std::string> & p) //<-- note &
{
p.push_back(std::string(TAnotherClass::Cchar1)+"/"+TAnotherClass::Cchar2);
}

Answer 2

Because you're trying to add two pointers. The + operator can't be overridden for char*.
You can do this:
p->push_back(std::string(TAnotherClass::Cchar1) + "/" + TAnotherClass::Cchar2);
Keep in mind the fact that std::string(...) as used above is a C-style cast using functional notation. It's equivalent, in this case, to static_cast<std::string>(...).
Whether you allow function style casts in your code is up to you. Some policies are against ALL C-style casts. In my previous workplace this particular use of them was allowed, but no other.