简单单链表的实现—C语言

本例简单实现了单链表，并附上调试（VS2013）过程，有助于深刻理解

单链表

链表是一种常见的重要的数据结构，它是动态的进行内存存储分配的一种结构。用数组存放数据时，必须事先定义固定的长度（即元素个数），但是事先难以确定有多少个元素时，则必须把数组定义的足够大，以保证成功。无疑，这会造成内存浪费，然而，链表则没有这种缺点，它可以根据需要，动态开辟内存单元。链表中的各个元素在内存中是可以不是连续存放的，但是要找到某一元素，必须知道它的地址，这就需要链表必须有一个头指针（head）。

本例包含
- 单链表的创建
- 单链表的查找
- 单链表的删除
- 单链表的打印
- 单链表的清除

实现代码

node.h

#ifndef _NODE_H_#define _NODE_H_typedef struct _node{    int value;    struct _node * next;} Node;#endif

main.c

#include <stdio.h>#include <stdlib.h>#include "node.h"//typedef struct _node{//  int value;//  struct _node* next;//} Node;typedef struct _list{    Node* head;} List;void list_add(List* pList, int number);void list_find(List* pList, int number);void list_delete(List* pList, int number);void list_print(List* pList);void list_clear(List* pList);int main(){    List list;    list.head = NULL;    printf("Please input some number of int: ");    int number = 0;    do{        scanf("%d", &number);        if (number != -1){            list_add(&list, number);        }    } while (number != -1);    printf(" this is list your input: ");    list_print(&list);    printf("\n");    printf("Please input one number of int,it will add that list: ");    int s = 0;    scanf("%d", &s);    list_add(&list, s);    printf(" this is list your input: ");    list_print(&list);    printf("\n");    printf("Please input one number of int,we will find it at your list: ");    int n = 0;    scanf("%d", &n);    list_find(&list, n);    printf("Please input one number of int,we will delete it at your list: ");    int m = 0;    scanf("%d", &m);    list_delete(&list, m);    printf(" this is list your input: ");    list_print(&list);    printf("\n");    list_clear(&list);    printf(" this is list is cleared! ");    return 0;}void list_add(List* pList, int number){    // add to liked-list    Node* p = (Node*)malloc(sizeof(Node));    p->value = number;    p->next = NULL;    Node* last = pList->head;    if (last){        // find last        while (last->next){            last = last->next;        }        //attach        last->next = p;    }    else{        pList->head = p;    }}void list_print(List* pList){    Node* p;    for (p = pList->head; p; p = p->next){        printf("%d\t", p->value);    }}void list_delete(List* pList, int number){    Node *p,        *q;    for (q = NULL, p = pList->head; p; q = p, p = p->next){        if (p->value == number){            if (q){                q->next = p->next;            }            else{                pList->head = p->next;            }            free(p);            break;        }    }}void list_find(List* pList, int n){    int isFind = 0;    Node* p;    for (p = pList->head; p; p = p->next){        if (p->value == n){            printf("Find!\n");            isFind = 1;            break;        }    }    if (!isFind){        printf("Not Find!\n");    }}void list_clear(List* pList){    Node *p,        *q;    for (p = pList->head; p; p = q){        q = p->next;        free(p);    }}

调试

1、单链表创建完成后如下图，大家可以想想内存上的情况：

2、充分理解for(;;){}

• 第一次运行到main.c的127行

• 第二次运行到main.c的127行