采用头插法和尾插法创建一个单链表。假设链表中的数据元素均为整数。

头插法创建单链表的代码如下：

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

typedef struct Node {
    int data;
    struct Node *next;
} Node;

Node *createListByHeadInsert(int arr[], int n) {
    Node *head = NULL;
    for (int i = 0; i < n; i++) {
        Node *node = (Node *)malloc(sizeof(Node));
        node->data = arr[i];
        node->next = head;
        head = node;
    }
    return head;
}

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int n = sizeof(arr) / sizeof(int);
    Node *head = createListByHeadInsert(arr, n);
    Node *p = head;
    while (p != NULL) {
        printf("%d ", p->data);
        p = p->next;
    }
    return 0;
}

尾插法创建单链表的代码如下：

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

typedef struct Node {
    int data;
    struct Node *next;
} Node;

Node *createListByTailInsert(int arr[], int n) {
    Node *head = NULL, *tail = NULL;
    for (int i = 0; i < n; i++) {
        Node *node = (Node *)malloc(sizeof(Node));
        node->data = arr[i];
        node->next = NULL;
        if (head == NULL) {
            head = tail = node;
        } else {
            tail->next = node;
            tail = node;
        }
    }
    return head;
}

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int n = sizeof(arr) / sizeof(int);
    Node *head = createListByTailInsert(arr, n);
    Node *p = head;
    while (p != NULL) {
        printf("%d ", p->data);
        p = p->next;
    }
    return 0;
}