priority queue of string in c - c

Question

This program is of priority queue where i am storing string as data and queue is created using linked list the element having least number (as priority no) has higher priority that is it will be inserted towards head node and so while the time of removing (pop or dequeue) that element will be removed first.(for eg 1 has higher Priority than 2)
#include<stdio.h>
#include<stdlib.h>
struct node {
char *string;
int priority;
struct node* next;
};
struct node *head;
struct node* getnewnode(char *s,int p){
struct node* newnode=(struct node*)malloc(sizeof(struct node));
newnode->string=s;
newnode->priority=p;
newnode->next=NULL;
return newnode;
}
void push(char* str,int p){
struct node* node1=getnewnode(str,p);
if(head==NULL){ //if the element is inserted in empty list
head=node1;
}
if(head->priority > p )
{
node1->next=head;
head=node1;
}
else
{
struct node* temp=head;
while(temp->next!=NULL&&temp->priority <= p){
temp=temp->next;
}
while(temp->next!=NULL&&temp->priority <= p) is correct or not because if the pushed element priority is matching than this new element will be placed after the present one(having same priority)
node1->next=temp->next;
temp->next=node1;
}
}
void pop(){
struct node* temp=head;
head=head->next;
free(temp);
}
char* peek(){
return head->string;
}
int main(){
head=NULL; //head is null initially
char a[10]="akash";
push(a,1);
char b[20]="rahul";
push(b,3);
printf("%s",peek());
}
It is not showing desired output but it is crashing
int main(){
head=NULL;
char* a=(char *)malloc(sizeof(char)*10);
a="akash";
push(a,1);
char* b=(char *)malloc(sizeof(char)*10);
b="rahul";
push(b,3);
char* c=(char *)malloc(sizeof(char)*10);
c="neymar";
push(c,1);
printf("%s",peek());
pop();
printf("%s",peek());
}
I give akash as priority 1 rahul as 2 and neymar again as 1 it should print akash and neymar for last two printf statements but it is printing akash rahul #dbush

Answer 1

In your push function, in the case where head is NULL, you set head to the new node, and then later try to put the node into the list again. You end up with the next field pointing to itself, so future inserts fall into an infinite loop.
When inserting into an empty list, you only need to set head to the new node and nothing else, so just return right away.
if(head==NULL){ //if the element is inserted in empty list
head=node1;
return;
}
Also, you should make a copy of the string that's passed in when you make a new node. Otherwise, you could end up with a pointer to memory that is no longer valid or multiple pointers pointing to the same buffer, with only the most recent update being viewable:
struct node* getnewnode(char *s,int p){
struct node* newnode = malloc(sizeof(struct node)); // don't cast return value of malloc
newnode->string = strdup(s); // create copy of given string
newnode->priority=p;
newnode->next=NULL;
return newnode;
}