c++ - Need Help Getting Classes to Interact With Each Other -

so basically, have write program kind of rpg game there different types of creatures. each creature object of class creature, , has member variables hitpoints, strength, etc.

what having trouble writing function handles dealing , taking damage between classes.

#include <iostream> #include <string> #include <stdlib.h>  using std::cout; using std::cin; using std::endl; using std::string;  //creature base class (type 0) class creature {   public:     creature(int, int, int);     int gettype() {return type;}     int getstrength(){return strength;}     int gethitpoints() {return hitpoints;}     void sethitpoints(int);     string getspecies();     void printstats();     void dealdamage(creature, creature);     void takedamage(int);    private:     int type;     int strength;     int hitpoints; };  creature::creature(int t, int s, int hp) {   type = t;   strength = s;   hitpoints = hp; }  void creature::printstats() {   cout << "this creature has: " << endl;   cout << strength << " strength" << endl;   cout << hitpoints << " hitpoints" << endl;   cout << "and of type " << type << "(" << getspecies() << ")" << endl; }  void creature::sethitpoints(int a) {   hitpoints = a; }  string creature::getspecies() {   switch(type)   {     case 0: return "creature";     case 1: return "human";     case 2: return "elf";     case 3: return "demon";     case 4: return "balrog";     case 5: return "cyberdemon";   } }  void creature::dealdamage(creature dealer, creature target) {   srand(5);   int damage;   damage = rand() % strength+1;   cout << dealer.getspecies() << " inflicts " << damage;   cout << " damage " << target.getspecies() << "!" << endl;   target.takedamage(damage); }  void creature::takedamage(int damage) {   sethitpoints((gethitpoints()-damage)); }  int main() {   creature monster1(0, 10, 100);   creature monster2(1, 7, 90);    monster1.printstats();   monster2.printstats();    monster1.dealdamage(monster1, monster2);   monster2.printstats();    return 0; } 

right now, output program gives me is:

this creature has: 10 strength 100 hitpoints , of type 0(creature) creature has: 7 strength 90 hitpoints , of type 1(human) creature inflicts 5 damage human! creature has: 7 strength 90 hitpoints , of type 1(human) 

so dealdamage() function seems working, takedamage() function not changing hitpoints of creature taking damage.

any appreciated.

the problem void creature::dealdamage(creature dealer, creature target)

firstly, called "pass value". new "creature" objects constructed , values of "creature" objects call function copied them. procedure executes, , these temporary creature objects eol - original creature objects never touched.

you need take pointer or reference original object. unless intending support kind of 3-way fight, shouldn't requiring both items anyway -- non-static member function, it's operating in context of 1 of creatures, hence syntax invoked it: monster1.dealdamage(monster1, monster2);

change dealdamage this:

void creature::dealdamage(creature& target) // takes reference {     //srand(5); <- cause rand() return same value. dont it.     //int damage; <- don't separate declaration , assignment when can avoid it.     int damage = rand() % strength+1;     cout << getspecies() << " inflicts " << damage          << " damage " << target.getspecies() << "!" << endl;     target.takedamage(damage); } 

you can use this->getspecies() if find using getspecies() unclear.

instead of srand(constant value) try 'srand(time(null))', or better still, once @ start of program.