inline function members inside a class

Question

I know that declaring a function (normal function not a method inside a class) as inline is a good practice when the function definition is small for performance and it save

Answer 1

There are two options to offer to the compiler to make a class function inline:

(1) Defining a function in the declaration of the class (in a header file)

class Human {

public:

    Human(const char* name);
    Human();

    // is implicit inline
    void lookAt(const char* name) const {
        std::cout << "I'm looking at " << name << std::endl;

    }

private:
    char _name[30]; 

}; 

(2) Using the inline keyword explicitly in the definition of the function (in a header file)

    // is explicit inline 
    inline void lookAt(const char* name) const {
        std::cout << "I'm looking at " << name << std::endl;

    }