// Directives to use classes
{$mode objfpc}
{$m+}

program exampleClass;

// Declaring a person Class
type Person = class
    // fields to hold data about a person
    private
        person_name : string;
        age : integer;
    
    public
        // constructor for intializing a class instance
        constructor c(n : string; a : integer);
        
        // methods to view and update person data
        procedure setName(n : string);
        function getName() : string;
        
        procedure setAge(a : integer);
        function getAge() : integer;
end;

// Defining the class methods

constructor Person.c(n : string; a : integer);
begin
    person_name := n;
    age := a;
end;

procedure Person.setName(n : string);
begin
    person_name := n;
end;

function Person.getName() : string;
begin
    getName := person_name;
end;

procedure Person.setAge(a : integer);
begin
    age := a;
end;

function Person.getAge() : integer;
begin
    getAge := age;
end;

var
    newPerson : Person;

begin
  
  // creating class instance
  newPerson := Person.c('Alice', 20);
  
  //output fields  
  writeln('The person''s name is ', newPerson.getName());
  writeln('The person''s age is ', newPerson.getAge());
  
  //updating fields
  newPerson.setName('Bob');
  newPerson.setAge(30);
  
  //output fields  
  writeln('The person''s name is ', newPerson.getName());
  writeln('The person''s age is ', newPerson.getAge());
end.