关于c:单链表反转

#include <stdio.h>#include <stdlib.h>struct ListNode {    int val;    struct ListNode* next;};void display(struct ListNode* head){    struct ListNode* current = head;    while(current != NULL) {        printf("%d\n", current->val);        current = current->next;    }}void push(struct ListNode* head, int val){    struct ListNode* current = head;    while(current->next != NULL) {        current = current->next;    }    current->next = (struct ListNode*)malloc(sizeof(struct ListNode));    current->next->val = val;    current->next->next = NULL;}struct ListNode* traverse(struct ListNode* head){    if (head == NULL) {        return NULL;    }    struct ListNode* newHead = NULL;    while(head != NULL) {        struct ListNode* temp = (struct ListNode*)malloc(sizeof(struct ListNode));        temp->val = head->val;        if (newHead == NULL) {            temp->next = NULL;        } else {            temp->next = newHead;        }        newHead = temp;        head = head->next;    }    return newHead;}int main(int argc, char const *argv[]){    struct ListNode* head = (struct ListNode*)malloc(sizeof(struct ListNode));    if (head == NULL) {        return 1;    }    head->val = 1;    head->next = NULL;    push(head, 2);    push(head, 3);    push(head, 4);    push(head, 5);    push(head, 6);    display(head);    struct ListNode* newHead = traverse(head);    printf("\n");    display(newHead);}