开发者

Variables not producing proper data

开发者 https://www.devze.com 2023-03-30 18:03 出处:网络
My variables aren\'t producing data like they should be. For whatever reason, my string is empty, yet when I try to execute my function, my character clearly passes the argument \"holland\" to the nam

My variables aren't producing data like they should be. For whatever reason, my string is empty, yet when I try to execute my function, my character clearly passes the argument "holland" to the name parameter upon construction. Despite this, when I make a call to get_name(), the string is returned as empty. Ontop of that, I have a static integer called "character_count", which is supposed to initialize at 0 and then increment upon every character creation to pass values to the character's unique id. Despite this, it's still not working as it should.

Could someone tell me please what I'm doing wrong?

here's my source:

#include "character.h"
#include <iostream>


int Character::char_count = 0;

Character::Character()
{
    this->char_id = char_count;
    char_count++;
}

Character::Character(std::string char_name, Race char_race, Gender char_gender)
{
    char_id = char_count;
    char_count++;
    name = char_name;
    race = char_race;
    gender = char_gender;
}

Character::~Character()
{

}

std::string Character::get_name()
{
    return this->name;
}

int Character::get_id()
{
    return this->char_id;
}

Race Character::get_race()
{
    return this->race;
}

Gender Character::get_gender()
{
    return this->gender;
}

Here's my header file:

#include <iostream>
#ifndef CHARACTER_H
#define CHARACTER_H

enum Race {HUMAN, DARK_ELF};
enum Gender {MALE, FEMALE};
class Character
{
public:
    Character();
    Character(std::string& char_name, Race& char_race, Gender& char_gender);
    ~Character();

    int get_id();
    std::string get_name();
    Race get_race();
    Gender get_gender();

private:
    int char_id;
    static int char_count;
    std::string name;
    Race race;
    Gender gender;
};

#endif // CHARACTER_H

Here's my main:

#include <QtCore/QCoreApplication>
#include <tinyxml/tinyxml.h>
#include "classowner.h"
#include "character.h"

int main(int argc, char *argv[])
{
    std::string holland_name = "holland";

    Character * holland = new Character(holland_name, HUMAN, MALE);
    delete holland;
    std::cout << "testing, mic...1, 2, 3...testing, tes开发者_开发问答ting. Bow, chica wow wowww!!1" << std::endl;
    std::cout << holland->get_id() << std::endl; //outputs as an 8 digit letter, when it should be either 0, or 1.
    std::cout << holland->get_name() << std::endl; //does not output at all.

    return 0;
}


That's because you delete the memory before you've finished with it. Try this instead

Character * holland = new Character(holland_name, HUMAN, MALE);
std::cout << "testing, mic...1, 2, 3...testing, testing. Bow, chica wow wowww!!1" << std::endl;
std::cout << holland->get_id() << std::endl;
std::cout << holland->get_name() << std::endl;
delete holland;

Only delete after you've finished with the object concerned. This kind of mistake invokes Undefined Behaviour, which means all bets are off and anything may happen when you run your code. In some ways you are lucky that there was an obvious error. Your program could have appeared to run successfully, and you would never have known there was a problem.


You deleted an object and then attempted to access it. That's Undefined Behaviour™ and anything may occur, including your compiler writer coming and beating you around the head with a baseball bat. You should simply do

Character holland(holland_name, HUMAN, MALE);
std::cout << holland.get_id();

As a general rule, if you don't really, really know what you're doing, never use new and delete - always use a class that's explicitly written to manage memory for you or just allocate the object on the stack.


Your code actually invokes undefined behaviour. Because you've deleted the pointer:

 delete holland;

And after this line, you're using it again. Undefined behaviour!

Now if its undefined behaviour, then the output cannot be explained after this!

0

精彩评论

暂无评论...
验证码 换一张
取 消