Any way to shorten String type in C++?

Question

Let's say I have function foo(string& s). If I would get C string, foo(char* s), I would simply call the function as foo("bar").
I wonder if I can somehow do it in the C++ String?

Somehow to shorten this:

string v("bar");
foo(v)

I'm using Linux GCC C++.

Answer 1

It is not working because the argument has to be a const reference:

void foo( const std::string& s )
//        ^^^^^

foo( "bar" );  // will work now

Answer 2

• If you want foo to only read from the argument you should write foo(const string& s).
• If you want foo to save the string somewhere (a class member..) you should write foo(string s).

Both versions allow you to write foo("bar"); which would't make any sense with a non const reference.

Answer 3

You could also try foo(string("bar")); to get your desired results, but since it is expecting a reference this wont work either.

So that means that your best bet is overloading for const char * to call the string method (this way you maintain only one method).

Answer 4

The std::string class does have an implicit conversion from const char*, so normally, passing a string literal into a function taking std::string works just fine.

Why it fails in your case is that the function takes its parameter as a non-const lvalue reference, and thus it requires an actual std::string lvalue to operate on.

If the function actually wants to take a non-const lvalue reference (i.e. it modifies the argument), you have to create an lvalue std::string and pass it (just like you do).

If the function does not modify the argument, change it to take by const-reference (const std::string&) or by value (std::string) instead; for both of these, passing an rvalue (like the std::string created by implicit conversion from const char*) will work and you can thus call the function with string literals.