How to create a linked list in C++? - c++

Question

I got these two structs
struct CamelZombie{
int hp;
int attack;
CamelZombie *next;
};
struct list_of_cz{
CamelZombie *head;
};
I've made a function to create linked list with given value:
void createCamelZombie(list_of_cz *&pZ, int z_hp, int z_attack, int N){
pZ = new list_of_cz;
pZ->head->hp = z_hp;
pZ->head->attack = z_attack;
CamelZombie *temp1 = pZ->head;
CamelZombie *temp2 = NULL;
for (int i = 0; i < N - 1 ; i++){
temp2 = new CamelZombie;
temp2->hp = z_hp;
temp2->attack = z_attack;
temp1->next = temp2;
temp1 = temp2;
}
}
Then i put it in function main like this, but then the propram crashed, don't know why.
list_of_cz *pZ = NULL;
createCamelZombie(pZ, z_hp, z_attack, N);
while (pList->head != NULL && pZ != NULL){
atPlant(numPlant(pList) - 1, pList)->hp -= pZ->head->attack;
if (atPlant(numPlant(pList) - 1, pList)->hp <= 0) deletePlant(numPlant(pList) - 1, pList);
int count = 0;
CamelZombie *z_temp;
z_temp = pZ->head;
while (z_temp){
if (count == 0) z_temp->hp -= allPlantAttack(pList, numPlant(pList) - 1);
else z_temp->hp -= allLaserAttack(pList); //trouble right here
if (z_temp->hp <= 0) deleteCamelZombie(pZ, count);
z_temp = z_temp->next;
count++;
}
Seem like i miss something when writing void createCamelZombie() 'cause the compiler tells me that z_temp->hp don't have a value. Please help me!

Answer 1

Preferably use an existing container like std::vector or std::list
#include <iostream>
#include <string>
#include <list>
struct CamelZombie{
std::string name; //added for demonstration purposes
int hp;
int attack;
//pointer to next zombie not required
};
std::list<CamelZombie> createCamelZombie2(int z_hp, int z_attack, int N) {
std::list<CamelZombie> result;
for (int i = 0; i < N; i++){
CamelZombie newZombie;
newZombie.name = "Zombie"+std::to_string(i);
newZombie.hp = z_hp;
newZombie.attack = z_attack;
newZombie.next = NULL;
result.push_back(newZombie);
}
return result;
}
Use the code like this.
int main() {
std::list<CamelZombie> listOfZombies2 = createCamelZombie2(10,20,10);
for(std::list<CamelZombie>::iterator list_iter = listOfZombies2.begin();
list_iter != listOfZombies2.end(); list_iter++)
{
std::cout<<list_iter->name<<std::endl;
}
}
If you really want to use your own linked list try the code below.
A seperate struct (list_of_cz) for the list is not required. Each zombie links to the next zombie. So just keep a pointer to the first zombie.
createCamelZombie function returns a pointer to the first zombie in the list (no need to use the function parameter (list_of_cz *&pZ) to get the zombie list)
Too many underscores and Z makes the code hard to read.
If you use pointers you need to clean up memory yourself.
.
struct CamelZombie{
std::string name; //added for demonstration purposes
int hp;
int attack;
CamelZombie *next;
};
CamelZombie* createCamelZombie(int z_hp, int z_attack, int N){
CamelZombie *result = NULL;
CamelZombie *work = NULL; //keep track of the last node in the list
for (int i = 0; i < N; i++){
//create new zombie
CamelZombie *newZombie = new CamelZombie();
newZombie->name = "Zombie"+std::to_string(i);
newZombie->hp = z_hp;
newZombie->attack = z_attack;
newZombie->next = NULL;
if (result==NULL) {
result = newZombie;
work =result;
} else {
work->next = newZombie;
work = newZombie;
}
}
return result;
}
Example of how to use the code.
int main() {
CamelZombie *listOfZombies = createCamelZombie(10,20,10);
CamelZombie *work = listOfZombies;
// print zombie names to screen ---------
while (work!=NULL) {
std::cout << work->name << std::endl;
work = work->next;
}
And free memory.
work = listOfZombies;
while (work!=NULL) {
CamelZombie *temp =work->next;
delete work;
work = temp;
}