Trouble with linked lists.(Graduation excercise)

[Vanapapi]

Hi, I'm trying to do a beginner excercise called "graduation". And I'm getting

Unhandled exception at 0x774a15de (ntdll.dll) in Graduation.exe: 0xC0000005: Access violation writing location 0x00000000.

I read a tutorial about linked lists and my understanding is that as far as you don't read/write beyond the last link, everything should be fine. Why does it do that?

Here is my code(void new_bunnies seems to be causing the problem). The exception doesn't occure at every excecution.:

#include <iostream>
#include <time.h>
#include <string>


enum sex1{male, female, vampire};

std::string name1[]={"Acanthus","Ambrosia","Aria","Atiyana","Avalon","Azalea","Baylyn","Braelyn","Cadence","Calliope","Cashmere","Cassia",
"Cayenne","Chavonne","Fauna","Flint","Forest","Forsythia","Glimmer","Harmony","Jescha","Keveen","Lark","Lilac","Meadow","Osment",
"Quintessence","Rontae","Serendipity","Serenity","Slate","Sonnet","Taffeta","Temperance"};

std::string color[]={"white", "brown", "black", "spotted"};

struct bunny{
public:
	sex1 sex;
	std::string color;
	std::string name;
	int age;
	bool radioactive_mutant_vampire_bunny;
	int alive;             //false 0
	bunny* next;
	int number_of_bunny;
	};

bunny* root;
bunny* conductor; 
int n,r;
std::string female_color[700];
int k;
int mutant_count;

int number_of_bunnies=0;

void create_bunny();

void create_5_bunnies();

void up_age();

void new_bunnies();

void create_bunny();

void kill_old();




int main()
{
	int bun=0;
	std::cout<<"male=0;female=1;vampire=2\n";

	create_5_bunnies();
	while(number_of_bunnies<1000){

	std::cout<<"NEW_BUNNIES";
	new_bunnies();
	std::cout<<"UP_AGE";
	up_age();
	std::cout<<"\nKILL_OLD\n";
	kill_old();

	std::cout<<number_of_bunnies<<" bunnies\n";

	if(number_of_bunnies==0){
		std::cout<<"All bunnies died";
		number_of_bunnies=1000;
		bun=1;
	}

	}
	
	if(bun!=1){std::cout<<"Bunny population exceeded 1000";}
	std::cin.get();
	return(0);
}

void create_5_bunnies(){
	root=new bunny;
	conductor=root;

	for(n=1;n<(5+1);n++){
		number_of_bunnies++;

		srand(time(NULL)+n);
		r=rand()%2+1;
		if(r==1)conductor->sex=male;
		else if(r==2)conductor->sex=female;

		srand(time(NULL)+n);
		r=rand()%4+1;
		if(r==1)conductor->color="white";
		else if(r==2)conductor->color="brown";
		else if(r==3)conductor->color="black";
		else if(r==4)conductor->color="spotted";

		srand(time(NULL)+n);
		r=rand()%34+0;
		conductor->name=name1[r];

		conductor->age=0;

		srand(time(NULL)+n);
		r=rand()%100+1;
		if(r==1||r==2){
			conductor->radioactive_mutant_vampire_bunny=true;
			conductor->sex=vampire;
		}
		else{conductor->radioactive_mutant_vampire_bunny=false;}

		
		std::cout<<"Bunny "<<conductor->name<<" was born!"<<conductor->sex<<"\n";

		conductor->alive=1;

		conductor->next=new bunny;
		conductor=conductor->next;
		conductor->next=0;
	}
	}

void up_age(){
	conductor=root;
	while(conductor!=NULL){
		conductor->age++;
		conductor=conductor->next;
	}
}

void new_bunnies(){
	int female_count=0;
	bool male_count=false;
	int bunnies_to_create=0;
	int bunnies_created=0;
	k=1;
	conductor=root;
	
	while(conductor!=NULL){  
		if(conductor->sex==female&&conductor->alive==1){female_count=female_count+1;
		female_color[k]=conductor->color;
		k++;
		female_color[k]=conductor->color;
		k++;
		}
		else if(conductor->sex==male){male_count=true;}
		conductor=conductor->next;
	}
	std::cout<<female_count<<" female bunnys.";
	bunnies_to_create=(female_count*2);
	std::cout<<bunnies_to_create<<" bunnies should born\n";
	if(bunnies_to_create>0){
		conductor=root;
		k=1;
		while(bunnies_created!=bunnies_to_create){
		if(conductor->alive==0){
			std::cout<<"creating bunny2\n";
			create_bunny();
			k++;
			if(conductor->next!=0){conductor=conductor->next;}
		}
		else if(conductor->next==0&&bunnies_created!=bunnies_to_create){
			std::cout<<"creating bunny3\n";
			create_bunny();
			bunnies_created++;
			k++;
			conductor->next=new bunny;
			conductor=conductor->next;
			conductor->next=0;
			}
		else{conductor=conductor->next;}
		}
	}
	conductor=root;
}

void create_bunny(){
	srand(time(NULL)+k);
		r=rand()%2+1;
		if(r==1)conductor->sex=male;
		else if(r==2)conductor->sex=female;

		conductor->color=female_color[k];

		srand(time(NULL)+k);
		r=rand()%34+0;
		conductor->name=name1[r];

		conductor->age=0;

		srand(time(NULL)+k);
		r=rand()%100+1;
		if(r==1||r==2){
			conductor->radioactive_mutant_vampire_bunny=true;
			conductor->sex=vampire;
		}
		else{conductor->radioactive_mutant_vampire_bunny=false;}

		number_of_bunnies++;
		
		std::cout<<"Bunny "<<conductor->name<<" was born!"<<conductor->sex<<"\n";

		conductor->alive=1;
}

void kill_old(){
	conductor=root;
	while(conductor!=NULL){
		if(conductor->age>10){
		conductor->alive=0;
		number_of_bunnies--;
		std::cout<<conductor->name<<" died!";}
		conductor=conductor->next;
	
	}
}

Here is the snippet of code where visual studio points me after the exception.

size_type max_size() const
		{	// return maximum possible length of sequence
		size_type _Num = this->_Alval.max_size();
		return (_Num <= 1 ? 1 : _Num - 1);
		}

[Pravesh Koirala]

Did you set the last link of conductor to NULL ? inf function create_5_bunnies

[Vanapapi]

conductor->next=0;
Line 120 I guess i did... is that important?
I found out that the problem was about array female_count size, set it to 1000 and it's okay now.