Priority queue not inserting element in ascending order - c

Question

This is the code of priority queue using linked list
i have two doubts in this code
1) This code is part of my insert function
if((*addofhead)->priority <= newnode->priority ){
struct node* temp=*addofhead;
while(temp->next!=NULL&&temp->priority <newnode->priority ){
temp=temp->next;
}
newnode->next=temp->next;
temp->next=newnode;
return;
}
why we can not do temp!=NULL in while loop instead of temp->next!=NULL because temp!=NULL will also make loop exit in one more iteration but it is crashing what is the reason of crashing
2)I want to make a priority queue such that the element which has least priority
should be removed first and elements which has same priority then the element will be removed first which was added first
input part from main function
insert(&head,3,5);
insert(&head,2,2);
insert(&head,1,1);
insert(&head,7,1);
insert(&head,11,1);
insert(&head,8,5);
insert(&head,9,5);
I am getting output for this 1 2 11 7 3 8 9 but its output should be 1 7 11 2 3 8 9
#include<stdio.h>
#include<stdlib.h>
struct node{
int data;
int priority;
struct node* next;
};
struct node* getnewnode(int data,int priority){
struct node* newnode=malloc(sizeof(struct node));
newnode->data=data;
newnode->next=NULL;
newnode->priority=priority;
return newnode;
}
void insert(struct node** addofhead,int data,int priority){
struct node* newnode=getnewnode(data,priority);
if(*addofhead==NULL){
*addofhead=newnode;
printf("head in insert is %d",*addofhead);
return;
}
if((*addofhead)->priority > newnode->priority){
newnode->next=*addofhead;
*addofhead=newnode;
return;
}
if((*addofhead)->priority <= newnode->priority ){
struct node* temp=*addofhead;
while(temp->next!=NULL&&temp->priority <newnode->priority ){
temp=temp->next;
}
newnode->next=temp->next;
temp->next=newnode;
return;
}
}
int removee(struct node** head){
if(*head==NULL)
return -1;
int temp=(*head)->data;
*head=(*head)->next;
return temp;
}
int main(){
struct node* head=NULL;
insert(&head,3,5); /// 3
insert(&head,2,2); /// 2,3
insert(&head,1,1); /// 1,2,3
insert(&head,7,1);
insert(&head,11,1);
insert(&head,8,5); /// 1,7,2,3
insert(&head,9,5);
struct node* temp=head;
while(temp)
{
printf(" %d ",temp->data);
temp=temp->next;
}
printf("\n head in main after insertion is %d",head);
}

Answer 1

why we can not do temp!=NULL in while loop instead of temp->next!=NULL (?)
Because the line after the loop has temp->next; #Jonathan Leffler.
The usual goal on marching down a linked list for insertion is to know the pointer of the previous node so its .next member may be updated.
Code has 2 functional problems
Comparing wrong priorities
// while(temp->next!=NULL&&temp->priority <newnode->priority ){
while(temp->next!=NULL&&temp->next->priority <newnode->priority ){
// ^^^^^^
Wrong compare when ==
// while(temp->next!=NULL&&temp->next->priority <newnode->priority ){
while(temp->next!=NULL&&temp->next->priority <= newnode->priority ){
// ^^^^^^ ^^
Also use %p to print a void *, not "%d" to print a pointer.
// printf("head in insert is %d",*addofhead);
printf("head in insert is %p",(void *) (*addofhead));
What was very useful to advance this was to create a helper function to print the data. It was then easy to call it after each insertion to narrow the issues.
void pq(const struct node* p) {
while (p) {
printf("(data %d,pri %d) ", p->data, p->priority);
p = p->next;
}
puts("");
}
I found OP's insert() overly complex. See #wildplasser.