Question

I have a linked list, now I want to walk through it and each time I advance in it, I move the current node to the beginning of list like this:

4 5 3 2 7
5 4 3 2 7
3 5 4 2 7
2 3 5 4 7
7 2 3 5 4

The code:

#include <stdio.h>
#include <stdlib.h>

typedef struct _node {
    int p;
    struct _node *next;
} node;

main(int argc, char **argv)
{
    int i, n;
    node *nod = NULL;
    node *nod2 = NULL;
    node *nod_tmp = NULL;

    node *nod_next = NULL;
    node *nod_before = NULL;

    printf("Enter n: ");
    scanf("%d", &n);
    for(i = 0; i < n; ++i)
    {
        nod_tmp = (node *)malloc(sizeof(node));
        scanf("%d", &nod_tmp->p);
        if (i == 0)
        {
            nod = nod2 = nod_tmp;
        }
        nod2->next = nod_tmp;
        nod2 = nod_tmp;
    }

    nod_tmp = nod;
    while (nod_tmp->next != NULL)
    {
        nod_before = nod_tmp; // save current node
        nod_next = nod_tmp->next->next; // save next node
        nod_before->next = nod_next; // link the previous with the next one
        nod_tmp->next = nod; // point the current node to the beginning of list
    }

    while(nod != NULL)
    {   
        printf("%d\n", nod->p);
        nod = nod->next;
    }
    return 0;
}   

Answer 1

nod_tmp = nod->next;
nod_before= nod;
while (nod_tmp != NULL)
{
     nod_before->next = nod_tmp->next;
     nod_tmp->next = nod;
     nod = nod_tmp;
     nod_tmp = nod_before->next;
}

Change your second loop to this loop above. Note that node_tmp points to the second node after the head and nod_before points to the first node. This way you avoid infinite loop.