C语言链表简单操作

struct ListNode {
    int data;
    struct ListNode *next;
};
    

void printList( struct ListNode *L )
{
    struct ListNode *p = L;
    while (p) {
        
        cout<<"data="<<p->data<<endl;
        p = p->next;
    }
     
}

struct ListNode* initList()
{
    struct ListNode *node=NULL;
    node=(struct ListNode*)malloc(sizeof(struct ListNode));
    memset(node,0,sizeof(struct ListNode));
    node->data=0;
    node->next=NULL;
    return node;
}
int listPushback(struct ListNode*L,int addNum)
{
    struct ListNode *temp=L;
    struct ListNode *pre=L;
    while(temp!=NULL)
    {
        pre=temp;
        temp=temp->next;

    }
    struct ListNode *newNode=(struct ListNode*)malloc(sizeof(struct ListNode));
    memset(newNode,0,sizeof(struct ListNode));
    newNode->data=addNum;
    newNode->next=NULL;
    pre->next=newNode;

    return 0;
}

int listPopBack(struct ListNode*L)
{
    if(L==NULL)
        return -1;
    struct ListNode *temp=L->next;
    struct ListNode *pre=L;
    while(temp!=NULL)
    {
        
        if(temp->next==NULL)
        {   
            pre->next=temp->next;
            int x=temp->data;
            free(temp);
            temp=NULL;
            
            break;
        }
        pre=temp;
        temp=temp->next;
        
    }
    return 0;
}

//首节点还没做处理(已处理)
int listDel(struct ListNode*L,int index)
{
    if(L==NULL || (index<0))
        return -1;
    struct ListNode *temp=L;
    struct ListNode *head=L;
    int i=0;
    
    if(index==0)
    {   
        temp=temp->next;
        while(temp!=NULL)
        {
            head->data=temp->data;
            temp=temp->next;
            head=head->next;
        }

        listPopBack(L);
        return 0;
    }

    while(temp!=NULL)
    {   

        if(i==index)
        {
            head->next=temp->next;
            free(temp);
            temp=NULL;
            return 0;
        }
        head=temp;
        temp=temp->next;
        i++;
        
    }

    return 0;
}

void freeList(struct ListNode *L)
{
    while(L!=NULL)
    {
        struct ListNode *temp=L;
        L=L->next;
        free(temp);
        cout<<"释放节点一次"<<endl;
    }
}
int main()
{   
    struct ListNode* nodeList=initList();
    listPushback(nodeList,1);
//  listPushback(nodeList,2);
//  listPushback(nodeList,3);
//  listPushback(nodeList,4);

    printList(nodeList);

    listDel(nodeList,0);
    //删除尾结点后
    cout<<"删除尾结点后"<<endl;
    printList(nodeList);


    freeList(nodeList);


    return 0;
}