// Chapter 5 - Program 2
#include <iostream.h>

class class_name {
int private_variable;//object--can only be altered and accessed by
                    //functions/methods within this class.
public://following can be used by all.
void set_value(int input_variable); //first "method" within this class--*only*
//means of changing private_variable!  the "void" means it returns no value, and
//the (int input_variable) means it receives an int variable from caller.
int get_value(void);// receives nothing from caller, but returns integer value
//of private_variable!  **only** means of getting to private_variable!
};
//define what the methods of the class "class_name" do.
//note the name of the class "prepended" to method names.
void class_name::set_value(int input_variable)//receives input_variable from
                                                  //caller.
{
private_variable = input_variable;//assigns input_variable value to
                    //private_variable.  again, *only* means of altering
                    //value of private_variable!
}

int class_name::get_value(void)//receives no input_variable--but returns value
//of private_variable onwhen called.  again, *only* means of returning
//value of private_variable!
{
return private_variable;//returns value to caller.
}

main()
{
class_name dog1, dog2, dog3;//declare 3 "objects" of class named "class_name".
int piggy;
//to access/call an method, use the "object's name, and the desired "method",
//seperated by a single dot, just like a structure call:
dog1.set_value(12);//passing an input_value to method "set_value.
//this is known as "sending a message" to that class.
dog2.set_value(17);
dog3.set_value(-13);
piggy = 123;

//retrieving private_variable's current value by sending a "message" to the
//get_value() method/function.
cout << "The value of dog1 is " << dog1.get_value() << "\n";
cout << "The value of dog2 is " << dog2.get_value() << "\n";
cout << "The value of dog3 is " << dog3.get_value() << "\n";
cout << "The value of piggy is " << piggy << "\n";
}




// Result of execution
//
// The value of dog1 is 12
// The value of dog2 is 17
// The value of dog3 is -13
// The value of piggy is 123