C 链表API

#include <stdio.h>
//链节 
struct Node{
    int Data;
    Node *next;
};

//链表类
class List{
    Node *head=NULL;
public:
    //在节点a前插入节点b 
    void Insert(int aData,int bData);
    //删除指定节点 
    void Delete(int aData);
    //清空节点
    void Clear();
    //返回链表链节数 
    int Length();
    //返回该链表所有连接的next指针，类型为数组 
    void GetAll(int* allNode);
    //从文件中加载链表数据
    void LoadFromFile(char filepath[]);
    //将链表保存到文件
    void SaveToFile(char filepath[]); 
    //获取链头 
    Node* GetHead(){return head;}
}; 

void List::Insert(int aData,int bData){
        Node *p,*q,*s;
        s=(Node*) new (Node);//动态分配一个节点
        s->Data=bData;//设b为此节点
        
        p=head; 
        if (head==NULL){
            //若是空表，使b作为第一个节点
            head=s;
            s->next=NULL; 
        } 
        else{
            if (p->Data==aData){ 
                //若a为第一个节点
                s->next=p;
                head=s; 
            }
            else{
                //查找节点a 
                while (p->Data != aData && p->next != NULL){
                    q=p;
                    p=p->next;  
                }
                if (p->Data == aData){
                    //若有节点a
                    q->next=s;
                    s->next=p;
                    printf("\n%d\n",aData);
                }
                else{
                    //若没有节点a,将b节点添加到末尾 
                    p->next=s;
                    s->next=NULL; 
                }
            }
        }
         
    } 

void List::Delete(int aData){
        Node *p,*q;
        p=head;
        if (p==NULL){
            //若是空表
            return ; 
        } 
        if (p->Data==aData){
            //若a为第一个节点
            head=p->next;
            delete p; 
        }
        else{
            while (p->Data!=aData && p->next !=NULL){
                //查找节点a
                q=p;
                p=p->next; 
            }
            if (p->Data ==aData){
                //若有节点a
                q->next =p->next;
                delete p; 
            }
        }
    
    } 

void List::Clear(){
        Node *p,*current; 
        current = head->next;
        p=head;
        delete p;
        while (current != NULL){
            current=p->next;
            p=current;
            delete p;
        }
        head=NULL;  
}

int List::Length(){
        int ListLengh=0;
        Node *current = head;
        while (current != NULL){
            current=current->next;
            ListLengh+=1;
        }
        return ListLengh;   
    } 

void List::GetAll(int* allNode){
        Node* current = head;
        current=head;
        //获取所有链接的next指针
        int count=0;
        while (current != NULL){
            *(allNode+count) = current->Data;
            current=current->next;
            count +=1;
        }       
    }

void List::LoadFromFile(char filepath[]){
    int data;
    FILE *fp;
    fp=fopen(filepath,"r");
    List::Clear();
    while (fscanf(fp,"%d\n",&data)){
        List::Insert(-1,data);
    }   
}

void List::SaveToFile(char filepath[]){
    FILE *fp;
    fp=fopen(filepath,"w+");
    Node *current = head;   
    while (current != NULL){
        fprintf(fp,"%d\n",current->Data);
        current=current->next;
    }
    fclose(fp);
}



int main(){
    List A;
    //插入数据 
    A.Insert(0,10);
    A.Insert(0,20);
    A.Insert(0,30);
    //输出数据长度
    printf("%d\n",A.Length());
    printf("==========分割线=============\n");
    //获取全部数据
    int a[A.Length()];
    A.GetAll(a);
    int i;
    for (i=0;i<3;i++){
        printf("%d\n",*(a+i));
    }
    printf("==========分割线=============\n");
    //删除data=10的数据
    A.Delete(10);
    //获取全部数据
    int b[A.Length()];
    A.GetAll(b);
    for (i=0;i<2;i++){
        printf("%d\n",*(b+i));
    }
    printf("==========分割线=============\n");
    //保存数据
    A.SaveToFile("lianbiao.txt");
    //再插入一条数据
    A.Insert(-1,40); 
    //打印
    int c[A.Length()];
    A.GetAll(c);
    for (i=0;i<3;i++){
        printf("%d\n",*(c+i));
    }
    printf("==========分割线=============\n");
    //从文件中加载数据
    A.LoadFromFile("lianbiao.txt");  
    //打印 
    int d[A.Length()];
    A.GetAll(d);
    for (i=0;i<A.Length();i++){
        printf("%d\n",*(c+i));
    }
    printf("==========分割线=============\n");
    
    return 0;
}