Class method and argument passing

c++, class, methods

Solution

I found it convenient, but why it worked if method parameter is reference to an object?

It works because your `lol` class defines a constructor accepting a `const char*` and which is not marked as `explicit`.

This authorizes the compiler to resolve the call `show("TEST")` by constructing a temporary object of type `lol`, passing the string literal `"TEST"` as the argument to the constructor, and binding your reference argument `l` to this temporary object.

To prevent implicit user-defined conversion sequences of this kind, mark your constructor as `explicit`:

class lol
{
    char * str;
public:
    explicit lol(const char * s);
//  ^^^^^^^^
    friend void show(const lol & l);
};

This way, the call `show("TEST")` will result in a compiler error.

Problem

I have been programming and I have spotted strange behavior in c++ classes. So I made simple class that contains string, constructor for that class and friend method(show) that prints string from object. But as you can see in main function. I pass to method(show) simple string and it works. I found it convenient, but why it worked if method parameter is reference to an object? ``` #include <iostream> using namespace std; class lol { char * str; public: lol(const char * s); friend void show(const lol & l); }; lol::lol(const char * s) //assign string to object { str = new char[strlen(s)+1]; strcpy(str,s); } void show(const lol & l) //prints string from object { cout << l.str; }; int main() { show("TEST"); //passing string but not an object return 0; }; ```

Original source