What is the meaning of const in this case???

[BNut]

Hello, Could anyone explain const for me in this case. this's a code

class Employee
{
    public:
        Employee(const string &,const string &);

        void setFirstName(const string &);
        string getFirstName()const;

        void setLastName(const string &);
        string getLastName()const;
private:
        string firstname,lastname;

};

Employee::Employee(const string &first,const string &last)
:firstname(first),lastname(last)
{

}
int main()
{
       SalariedEmployee salariedEmp("John","Smith");
       return 0;
}

my problem is what different when I put const in different position? like these two functions?

void setFirstName(const string &);
        string getFirstName()const;

[Peter87]

void setFirstName(const string&);
const here means that the function is not allowed to manipulate the string being passed to the function.

string getFirstName() const;
const here means that the function is not allowed to manipulate the object itself (its member variables).

[BNut]

Thank you Peter87