Hi, I'm trying to do the last excercise of c++ beginner exercises.
I'm gettingI 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?Code:
Unhandled exception at 0x774a15de (ntdll.dll) in Graduation.exe: 0xC0000005: Access violation writing location 0x00000000.
Here is my code(void new_bunnies seems to be causing the problem). The exception doesn't occure at every excecution.
Here is the snippet of code where visual studio points me after the exception.Code:#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()
{
srand(time(NULL));
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++;
r=rand()%2+1;
if(r==1)conductor->sex=male;
else if(r==2)conductor->sex=female;
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";
r=rand()%34+0;
conductor->name=name1[r];
conductor->age=0;
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(){
r=rand()%2+1;
if(r==1)conductor->sex=male;
else if(r==2)conductor->sex=female;
conductor->color=female_color[k];
r=rand()%34+0;
conductor->name=name1[r];
conductor->age=0;
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;
}
}
Code:size_type max_size() const
{ // return maximum possible length of sequence
size_type _Num = this->_Alval.max_size();
return (_Num <= 1 ? 1 : _Num - 1);
}
