C++ strcpy non-constant expression as array bound -

I came back to C ++ after a long time in C #, PHP and other stuff and I have some strange things :

  temp.name = new char [strlen (name) + strlen (r.name) + 1];  

this compiled

  temp.name = (char *) malloc (size (four [strlen (name) + strlen (r.name) + 1 ]));  

it is not (temp.name is a char *)

compiler error

error C2540: non-array bindings Constant expression in form

Do anyone know what the problem can be and how it can be treated? Thank you

size (...) expects a continuous compilation- time expression. strlen is not a compile-time expression, it is a function that needs to be executed to get results. Therefore, the compiler is not able to reserve enough storage for the declared array as follows:

  Four C [Stellen ("Hello")];  

Although the length of the string is clearly 5, the compiler does not know.

To prevent this from getting worse, sizeof here. Instead:

  four * c = (four *) molk (strangle (name) + strannel +1);  

This gives you an indication of n bytes in return. sizeof (char) == 1 is always correct, so the number of bytes in the buffer is equal to the size that you can store it. For a different type of malloc array, multiply with the static size of an array element:

  int * c = (int *) malloc (sizeof (int ) * 100);  

This is okay, because sizeof applies to a compiled time expression. Of course, the C ++ method is pretty clean:

 < Code> int * c = new int [100];