class类中的函数声明后面跟const的意思是什么?

#pragma once
#include<string>
using namespace std;
class Person
{
public:
   
    Person(){ lname = ""; fname[0] = '\0'; }
    Person(const string &ln, const char *fn = "Heyyou");
    void Show()const;
    void FormalShow()const;
   

private:
    static const int LIMIT = 25;
    string lname;
    char fname[LIMIT];
};