C program to reverse a linked list

PROGRAM:

#include <stdio.h>
#include <stdlib.h>
//Creating structure
struct node
{
    int data;
    struct node *link;
}*first=NULL;

struct node * create(struct node *);
void disp(struct node *);
struct node * rev(struct node *);

//main function
int main()
{
    printf("\nEnter elements to create linked list\n");
    first=create(first);
    printf("\nLinked list created!\n");
    disp(first);
    first=rev(first);
    printf("\nReversed Linked List\n");
    disp(first);
    return 0;
}

//function to create linked list
struct node * create(struct node *first)
{
    struct node *new_node;
    int choice=0;

    do
    {
        new_node=(struct node *)malloc(sizeof(struct node));
        printf("\nEnter  an element\n");
        scanf("%d",&new_node->data);
        new_node->link=NULL;
        if(first==NULL)
            first=new_node;
        else
        {
            new_node->link=first;
            first=new_node;
        }
        printf("\nEnter 1 to continue, 0 to stop\n");
        scanf("%d",&choice);
    }while(choice==1);
    return first;
}

//function to display linked list
void disp(struct node *first)
{
    struct node *temp;
    if(first==NULL)
        printf("\nDisplay not possible, Linked list empty\n");
    else if(first->link==NULL)
    {
        printf("Displaying linked list elements:\n");
        printf("%d",first->data);
    }
    else
    {
        printf("Displaying linked list elements:\n");
        temp=first;
        while(temp!=NULL)
        {
            printf("%d\t",temp->data);
            temp=temp->link;
        }
    }
}

//function to reverse linked list
struct node * rev(struct node * first)
{
    struct node *x,*y,*z;
    x=first;
    y=first->link;
    z=first->link->link;
    while(z!=NULL)
    {
        y->link=x;
        x=y;
        y=z;
        z=z->link;
    }
    y->link=x;
    first->link=NULL;
    first=y;
    return first;
}

OUTPUT:

Enter elements to create linked list

Enter  an element
10

Enter 1 to continue, 0 to stop
1

Enter  an element
20

Enter 1 to continue, 0 to stop
1

Enter  an element
30

Enter 1 to continue, 0 to stop
1

Enter  an element
40

Enter 1 to continue, 0 to stop
1

Enter  an element
50

Enter 1 to continue, 0 to stop
0

Linked list created!
Displaying linked list elements:
50      40      30      20      10
Reversed Linked List
Displaying linked list elements:
10      20      30      40      50