Create a process control block using this singly linked list below and c++. PCB

Question

Create a process control block using this singly linked list below and c++. PCB must contain int pid, pid meaning process identifier, char[20] name, and int state. Define INIT, READY, BLOCKED, and RUNNING. Thanks!

#include <iostream>
#include <cstdlib>

using namespace std;

// creating node object with variable data
struct node{

int data;
// creating a pointer to next node in chain
node *next;
};

// for displaying output
void display(node* head);

// for inserting node, pointer to head and integer value, d.
node* insert(node* head, int d){

// allocate piece of memory, to create new node
struct node *node = (struct node*)malloc(sizeof(struct node));

// make head a pointer to last, only singly linked list.
struct node *last = head;

// for inserting integer in main function
node-> data = d;
// set next equal to null to avoid garbage data
node-> next = NULL;
// if head
if(head == NULL){
// let node equal head
head = node; //if list empty, update head as first element

return head; //return head

}
while(last-> next != NULL)
    // grab what last's next is, set equal to last
    last = last->next;

last->next = node; //else update new element as next to last element

return head;

}

node* remove(node* head, int d){
// create pointer to head and temp pointer
struct node *p = head, *temp;
// while p's next is null and p's next node contains no data
while(p-> next != NULL && p-> next -> data != d)

p = p -> next; //traverse list until element not found
// value does not exist
if(p -> next == NULL){
    cout << "Key not found "; // end of list
    return NULL;
}
// keep traversing list
temp = p -> next;
//
p -> next = p-> next -> next; //updates link

// so we don't have any memory leaks.
free(temp);

return head;
}

int main(){

// pointer to head
node *head;
// testing numbers <=3
for (int i=1; i<=3; i++)

// insert numbers into head
head = insert(head, i);

cout << "Original List : ";

display(head);

cout << "List after deletion : ";
// remove number 2 in chain
head = remove(head, 2);

display(head);

return 0;

}

void display(node* head){

// create new pointer temp and point it to last node

node * temp = head;

// while nodes are present

while(temp != NULL){
    cout << temp -> data << " -> ";
//iterate temp across the next node
    temp = temp -> next;
}
    cout << endl;
}

Explanation / Answer

#include <iostream>
#include <cstdlib>
#include<string.h>
#include<stdlib.h>

using namespace std;

#define INIT 1
#define READY 2
#define RUNNING 3
#define BLOCKED 4
// creating node object with variable data
struct node{
int pid;
char name[20];
int state;
// creating a pointer to next node in chain
node *next;
};
// for displaying output
void display(node* head);
// for inserting node, pointer to head and integer value, d.
node* insert(node* head, int pi, char *nm, int st){
// allocate piece of memory, to create new node
struct node *node = (struct node *)malloc(sizeof(struct node));
// make head a pointer to last, only singly linked list.
struct node *last = head;
// for inserting integer in main function
node->pid = pi;
strcpy(node->name,nm);
node->state = st;
// set next equal to null to avoid garbage data
node-> next = NULL;
// if head

if(head == NULL){
// let node equal head
head = node; //if list empty, update head as first element
return head; //return head
}
while(last-> next != NULL)
    // grab what last's next is, set equal to last
    last = last->next;
last->next = node; //else update new element as next to last element

return head;
}
node* remove(node* head, int d){
// create pointer to head and temp pointer
struct node *p = head, *temp;
// while p's next is null and p's next node contains no data
while(p-> next != NULL && p-> next ->pid != d)
p = p -> next; //traverse list until element not found
// value does not exist
if(p -> next == NULL){
    cout << "Key not found "; // end of list
    return NULL;
}
// keep traversing list
temp = p -> next;
//
p -> next = p-> next -> next; //updates link
// so we don't have any memory leaks.
free(temp);
return head;
}
int main(){
// pointer to head
node *head;
head = NULL;
// testing data <=3
for (int i=1; i<=3; i++)
// insert data into head
head = insert(head, i,(char *)"name",i);

cout << "Original List : ";
display(head);
cout << "List after deletion : ";
// remove number 2 in chain
head = remove(head, 2);
display(head);

return 0;
}
void display(node* head){
// create new pointer temp and point it to last node
node * temp = head;
// while nodes are present
while(temp != NULL){
   cout << temp->pid << " " << temp->name << " " <<temp->state << endl;;
   //iterate temp across the next node
   temp = temp -> next;
}
    cout << endl;
}

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