C program to find the Number of Occurrences of all the elements present in the Linked list

PROGRAM:

/*list refers to original linked list and occur list refers to the list which is used to store the elements and its corresponding occurrences*/

#include<stdio.h>
struct node
{
int data;
struct node *next;
} *head,*temp,*temp1,*first,*last;
/*Structure occur is to store the element(in data) and its corresponding occurrences (in count) and next is to store next occur nodes address*/
struct occur
{
int data;
int count;
struct occur *next;
} *head1,*occur1,*newoccur;
void create();
void print();
void occurrence();
void printOccur();
void main()
{
create();
printf("\nElements in the entered list:\n");
print();
occurrence();
printf("\nElements and their corresponding occurrences:\n");

printf("Element\tOccurrences:\n\n");
printOccur();
}
void create()
{
int num;
printf("\nEnter element or enter -1 to exit\n");
head=(struct node*)malloc(sizeof(struct node));
scanf("%d",&num);
if(num==-1)
{
head=NULL;
}
else
{
head->data=num;
head->next=NULL;
}
while(head!=NULL)
{
printf("\nEnter element or enter -1 to exit\n");
scanf("%d",&num);
if(num==-1)
{break;}
else
{
temp=head;
while(temp->next!=NULL)
{
temp=temp->next;
}
temp1=(struct node*)malloc(sizeof(struct node));
temp1->data=num;
temp1->next=NULL;
temp->next=temp1;
}
}
}
/*occurrence function calculates the number of occurrences of the elements.*/
void occurrence ()
{
int found;
/*first element in occur list is created and it is named as head1*/
head1=(struct occur*)malloc(sizeof(struct occur));
head1->data=head->data;
head1->count=0;
head1->next=NULL;
for(temp=head;temp!=NULL;temp=temp->next)
{
found=0;
for(occur1=head1;occur1->next!=NULL;occur1=occur1->next)
{
/*if the element in the list is found in the occur list then its count value is incremented by 1.*/
if(occur1->data==temp->data)
{
found=1;
occur1->count++;
}
}
/*if the element is not found in the occur list then new node is created for that element and it is placed at the starting of the occur list(to minimize complexity)*/
if(found==0)
{
newoccur=(struct occur *)malloc(sizeof(struct occur));
newoccur->data=temp->data;
newoccur->count=1;
newoccur->next=head1;
head1=newoccur;
}
}
}
void print()
{
struct node *head1=head;
while(head1!=NULL)
{
printf("%d\t",head1->data);
head1=head1->next;
}
}
/*printOccur function is to print the elements and corresponding occurrences in the occur list*/
void printOccur()
{
struct occur *temp=head1;
while(temp->next!=NULL)
{
printf("%4d%8d\n",temp->data,temp->count);
temp=temp->next;
}
}
/*In occur list new node is inserted at starting just for reducing complexity....*/
OUTPUT: