is this style of c++ programming good?

Hi,
I'm thinking about implementing the all the function details in the header file, for example I have the following code in Box.h :

class Box{
public:
Box(int num){
this->num = num;
}

void Rotate(){
//many lines of code here
}
private:
int num;
};

Instead of writing Box::Rotate(){
//many lines of code here
} in my cpp file , I implement the Rotate function in the header file.
this style is a little bit like java

Do you think this is a good coding style?

Usually it's best to have the declarations in the header file and definitions in a source file. Putting the definition of methods in the class makes them inline and that can bloat your code a lot if you aren't careful.

You forgot code brackets.
Now you must diiiiiiieeeee