单链表

//单链表
typedef struct LNode{
    int data;
    struct LNode* next;
}LNode;

LNode L;

//初始化
void InitList(LNode *&L){
    L = (LNode*)malloc(sizeof(LNode));
    L -> next = NULL;
}

//判断线性表是否为空
bool ListEmpty(LNode *L){
    return L -> next == NULL;
}

//尾插法
void CreatelistR(LNode *&L,int a[],int n){
    LNode *s,*r;   //s指向新申请的结点
    r = L;
    for(int i = 0 ; i < n ; i++){
        s = (LNode*)malloc(sizeof(LNode));
        s -> data = a[i];
        r -> next = s;
        r = s;
    }
    r -> next = NULL;
}

//头插法
void CreateListF(LNode *&L,int a[],int n){
    LNode *s;
    for(int i = 0 ; i < n ; i++){
        s = (LNode*)malloc(sizeof(LNode));
        s -> data = a[i];
        s -> next = L -> next;
        L -> next = s;
    }
}


//插入
bool InsertList(LNode *&L,int i,int x){
    int n = 0;
    LNode *r = L , *s;
    if(i < 0)return false;
    while(n < i-1 && r != NULL){
        r = r -> next;
        n++;
    }
    if(r == NULL)                     //r = i-1;
        return false;
    else{
        s = (LNode*)malloc(sizeof(LNode));
        s -> data = x;
        s -> next = r -> next;
        r -> next = s;
        return true;
    }
}

//删除
bool DeleteList(LNode *&L,int i,int &e){
    int n = 0;
    LNode *r = L , *q;
    if(i <= 0)return false;
    while(n < i-1 && r->next != NULL){
        r = r -> next;
        n++;
    }
    if(r == NULL)
        return false;
    else{
        q = r -> next;
        if(q == NULL)
            return false;
        e = q -> data;
        r -> next = q -> next;
        free(q);
        return true;
    }
}

//按元素值查找
int FindElem(LNode *L , int e){
    int n = 1;
    LNode *r = L -> next;
    while(r!=NULL && r -> data != e){
        r = r -> next;
        n++;
    }
    if(r == NULL)
        return 0;
    else
        return n;
    
}

//按位置查找
bool GetElem(LNode* L, int i, int &e){
    int n = 0;
    LNode * r =L;
    if(ListEmpty(L))
        cout<<"空表"endl;
    if(i <= 0)
        return false;
    while(r != NULL && n < i){
        n++;
        r = r -> next;
    }
    if(r == NULL)
        return false;
    else{
        e = r -> data;
        return true;
    }
}

//求链表表的长度
int ListLength(LNode *L){
    int n = 0;
    LNode *r =L;
    while(r -> next != NULL){
        n++;
        r = r -> next;
    }
    return n;
}