Herencia de Clases en C++

[blackwind]

he aqui un ejemplito que tome de un tuto :
int main()
{

// Instantiate our wizard
WIZARD wizard("Merlin",50,40,30,70);

char *wizard_name = wizard.getName(); // Get the name
int life = wizard.getLife(); // Get the life
int spellPower = wizard.getSpellPower(); // Get the spell power

// Print it
cout << wizard_name << "'s life = " << life << "." << endl;
cout << wizard_name << "'s spell power = " << spellPower << "." << endl << endl;
return 0;
}






luego en el .h
#define MAX_PLAYER_NAME 25 // The maximum number of characters in a player's name

#include <stdlib.h>
#include <string.h>

// This will encompass attributes (variables, characteristics) that ALL players have
// for this tutorial
class PLAYER
{
public:

// Our constructors
PLAYER();
PLAYER(char *player_name, int L, int I, int S); // L == life
// I == intellect
// S == strength

/** Data Access Functions **/

char* getName() { return name; }

int getLife() { return life; }

/** End of Data Access Functions **/


private:

char name[MAX_PLAYER_NAME]; // The name of the player

int life; // The amount of "life" the player has -- Range is 0 - 1000
int intellect; // How "smart the player is -- Range is 0 - 100
int strength; // How "strong" the player is -- Range is 0 - 100

bool alive; // Is the player alive or dead

};



/*
Okay here is where the power of inheritance (deriving from classes is)
We are going to inherit the WIZARD class from the PLAYER class meaning "certain aspects
of the PLAYER class will exist in the WIZARD class as if the code was cut 'n paste
directly into the WIZARD class" -- Notice I said "certain aspects", depending on how we
inherit, differnt aspects (member variables, methods) will be accessible to us in
the WIZARD class

*/

// The single colon ':' signifies we are inheriting -- The "public" means that everything that
// is public to the PLAYER class will be public to the WIZARD class
class WIZARD : public PLAYER
{
public:

// Constructors
WIZARD();
WIZARD(char *player_name, int L, int I, int S, int SP); // L == life
// I == intellect
// S == strength
// SP == spellPower

/** Data Access Functions **/

int getSpellPower() { return spellPower; }

/** End of Data Access Functions **/

private:

int spellPower; // The power of the wizard's spell -- Range 0 - 100

};




y en la utilizacion:


#include "player.h"

// Our constructors ---

// Our default constructor will set the player name to NULL
// It will set life to 100 units and intellect and strength to 20 units
// Since we a creating a player, it's obviously alive
PLAYER::PLAYER():life(100),intellect(20),strength( 20),alive(true)
{
// Clear the name to NULL
memset(name,0,MAX_PLAYER_NAME);
}

// An overloaded constructor will set the name, life, strength and intellect of the
// player to values passed in
PLAYER::PLAYER(char *player_name, int L, int I, int S):life(L),intellect(I),strength(S),alive(true)
{
// Clear the name to NULL
memset(name,0,MAX_PLAYER_NAME);

if(player_name)
{
int len = strlen(player_name); // Get the length of the player name passed in

// If it's greater than the space we are allotting for player names
// cut it off
if(len >= MAX_PLAYER_NAME)
{
for(int i = 0; i < MAX_PLAYER_NAME; i++)
name[i] = player_name[i];

name[MAX_PLAYER_NAME - 1] = NULL;
}
else
strcpy(name,player_name); // Just copy over the player name
}

} // end of PLAYER::PLAYER(char *player_name, int L, int S, int I)


// Our WIZARD class default constructor -- This set the spellPower to a value of 10
// Everything else (like "life" for example) will get set by the default PLAYER constructor
// that WILL be called
WIZARD::WIZARD():spellPower(10) { /* do nothing */ }

// Now this is our constructor that takes parameters --
// To set the PLAYER variables (such as life), we HAVE to EXPLICTILY call the PLAYER's constructor
// Otherwise the default constructor for the PLAYER will get called and these variables WILL NOT get set
WIZARD::WIZARD(char *player_name, int L, int I, int S, int SP):PLAYER(player_name,L,I,S),spellPower(SP)
{
/* do nothing */
}


espero te sirva