Begginer Excercise

[10oTURfi]

Soo... After learning some more C++ I decided to write the "Graduation" program from http://www.cplusplus.com/forum/articles/12974/ .
But I am stuck at very begining; This code below compiles but program instantly crashes.

Help :)

#include <iostream>
#include <time.h>
#include <string>
#include <cstdlib>
using namespace std;

class bunny{
public:
	bunny();
	void demo(){ cout << age << " " << color << " " << isvamp << " " << name << " " << sex << endl; }
private:
	int age;
	bool isvamp;
	string color;
	string sex;
	string name;
protected:
};

bunny::bunny(){
	//Lists, consts and rand stuff
	const int name_num = 4;
	int temp;
	string name_list[name_num] = { "Pero", "Jozo", "Darko", "Ivan" };
	string color_list[4] = { "White", "Black", "Brown", "Spotted" };

	//Init age
	age = 0;

	//Init isvamp
	temp = rand() % 100+1;
	if(temp == 1 || (temp == 2))
		isvamp = true;
	else isvamp = false;

	//Init sex
	temp = rand() % 2+1;
	if(temp == 2)
		sex = "female";
	else sex = "male";

	//Init name
	temp = rand() % name_num+1;
	name = name_list[temp];
	
	//Init color
	temp = rand() % 4+1;
	color = color_list[temp];
}
	

int main(){
	//Init rand
	srand(time(NULL));

	//DEMO
	bunny test;
	test.demo();


	//END
	return 0;
}

[Moschops]

Running exactly that code on ideone.com does not always lead to a crash:

http://ideone.com/F6aJv

The output, however, does indicate that something is going wrong with colour selection. In your code, it is possible to read color[4]; however, that is off the end of the array, so it's possible to read the wrong memory. This is something that can lead to a segFault. Same with reading the name.

[10oTURfi]

Mmm this is getting weird. Sometimes crashes, sometimes works. Also ideone.com outputed string from name_list as value in color string, which is pretty impossible if you read code carefully.

edit: yah. im so stupid.

[10oTURfi]

OW and one more thing.

How do I create new bunny objects during runtime of program?

[Moschops]

You can make them on the stack, like this:

bunny test;
test.demo();

or on the heap, like this:

bunny* pTest = new (bunny);
pTest->demo();

[10oTURfi]

Need more help. I have problems with creating new bunnies onto array of bunny objects. Also I figured that when bunnies die, and I delete their object, there will be empty spot in array. How should I shift back all other bunnies to prevent those holes?

Ok I know how does this look. But I swear it sounded like brilliant idea before i got to computer and compiled it... :D

int main(){
	//Init/Start game
	srand(time(NULL));
	int num_of_bunnies = 5;
	bunny *pBunny = new bunny[num_of_bunnies];

//Create new bunnies each turn if its possible?
	for(int i=0; i<num_of_bunnies; i++){
		if((*pBunny[i]->getSex() == "male") && (*pBunny[i]->getAge() >=2)){
			for(int i=0; i<num_of_bunnies; i++){
				if((*pBunny[i]->getSex() == "female") && (*pBunny[i]->getAge() >=2)){
				num_of_bunnies += 2;
				//bunny *pBunny = new bunny[num_of_bunnies];
				}
			}
		}
	}
	return 0;

class bunny{//Bunny class file
public:
	bunny();
	~bunny();
	void setAge() {age++;}
	int getAge() {return age;}
	string getSex() {return sex;}
private:
protected:
	int age;
	bool isvamp;
	string color;
	string sex;
	string name;
};

EDIT:
If I do this, program compiles, but I cant add any new bunnies to array!

	bunny pBunny[5];

	for(int i=0; i<num_of_bunnies; i++){
		if((pBunny[i].getSex() == "male") && (pBunny[i].getAge() >=2)){
			for(int i=0; i<num_of_bunnies; i++){
				if((pBunny[i].getSex() == "female") && (pBunny[i].getAge() >=2)){
				num_of_bunnies += 2;
				//bunny *pBunny = new bunny[num_of_bunnies];
				}
			}
		}
	}

EDIT2: And if I try to allocate memory for all of the bunnies at begining, constructor goes mad (see above...)

[hanst99]

If you need to remove elements from the middle of the collection during runtime, it's usually a sign that using a list may be a good idea.

http://cplusplus.com/reference/stl/list/

[Moschops]

As Hanst99 indicates, if you want your arrays to be flexible and expandable and able to have bits deleted and so forth, you're crying out for proper C++ containers.

[10oTURfi]

If you need to remove elements from the middle of the collection during runtime, it's usually a sign that using a list may be a good idea.

Oh.. wow. That looks like something I was looking for. Thanks alot!