#include <stdio.h>

#include <stdlib.h> #include <conio.h> #include <malloc.h>

#define DATA_TYPE int

typedef struct node {     DATA_TYPE data;     struct node* next; }LinkList, *Pointer;

void menu();                     /*显示菜单*/

int readChoice();                   /*读菜单选项*/ void cleanBuffer();                 /*清除缓存*/ void addElement();                  /*添加元素*/ void showElement();                 /*显示所有元素*/ Pointer moveToTag(int tag);         /*根据tag移动偏移量*/ int removeByPostion();              /*根据位置删除元素*/ int getLinkListSize();              /*获得链表大小*/ void frontToBack(Pointer tail);     /*从前向后添加数据*/ void backToFront(Pointer tail);     /*从后向前插入元素*/ Pointer createLinkList();           /*从前向后创建链表*/ Pointer moveTail();                 /*移动到链表尾部*/ DATA_TYPE findElementByPostion();   /*根据位置查找元素*/

Pointer pointer = NULL;

int main(void) {     int choice = 0;     DATA_TYPE data = -1;

    menu();

    while (1)     {         printf("\n");         choice = readChoice();

        switch (choice)

        {             case 1:                 addElement();                 printf("add success!!!");                 break;             case 2:                 if (removeByPostion())                 {                     printf("Remove success!!!");                 }                 else                 {                     printf("Positon error!!");                 }                 break;             case 3:                 data = findElementByPostion();                 if (data != -1)                 {                     printf("%d", data);                 }                 else                 {                     printf("haven't data!!");                 }                 break;             case 4:                 showElement();                 break;             case 5:                 exit(0);                 break;             default: printf("Option does not match!!!");                 break;         }     }

    getch();

    return 0; }

void menu()

{     printf("\t\n#################################\n");     printf("*\t 1.AddElement\t\t*\n");     printf("*\t 2.RemoveByPostion\t*\n");     printf("*\t 3.FindElementByPostion\t*\n");     printf("*\t 4.ShowElement\t\t*\n");     printf("*\t 5.Quit\t\t\t*");     printf("\t\n#################################\n\n"); }

int readChoice()

{     int choice = 5;     printf("\nPlease input choice:");     while (scanf("%d", &choice) != 1)     {         printf("Input error!!!\n");         printf("Please input again:");         cleanBuffer();     }

    return choice;

}

void cleanBuffer()

{     int c = 0;     while ((c = getchar()) != '\n' && c != EOF ); }

void addElement()

{     int o = 0;     Pointer tail = NULL;

    if (pointer == NULL)

    {         tail = pointer = createLinkList();     }     else     {         tail = moveTail();     }         printf("1.From the front to the back\t");     printf("other.From the back to the front\n");     printf("Please input add data method:");     while (scanf("%d", &o) != 1)     {         printf("Input error!!!\n");         printf("Please input again:");         cleanBuffer();     }

    printf("[*Notice : Please enter -1 to end]\n");

    if (o == 1)     {         frontToBack(tail);     }     else     {        backToFront(tail);     } }

Pointer createLinkList()

{     pointer = (Pointer)malloc(sizeof(LinkList));     pointer->next = NULL;     pointer->data = 0;

    return pointer;

}

Pointer moveTail() {     Pointer current = pointer->next;     while (current->next != NULL)     {         current = current->next;     }

    return current;

}

int getLinkListSize()

{     int count = 0;     Pointer current = pointer;     while (current->next != NULL)     {         current = current->next;         count++;     }

    return count;

}

void showElement()

{     Pointer current = pointer->next;     if (current == NULL)     {         printf("Linklist is empty!!!");     }     else     {         printf("Elements list:\n");         while (current != NULL)         {             if (current->next == NULL)             {                 printf("%d", current->data);             }             else             {                 printf("%d-->", current->data);             }             current =  current->next;         }     }

    printf("\n");

}

Pointer moveToTag(int tag)

{     int i = 0;     Pointer current = pointer;     while (i++ < tag)     {         current = current->next;     }

    return  current;

}

int removeByPostion()

{     int pos = 0;     Pointer front = NULL;     Pointer rear = NULL;     Pointer current = NULL;

    printf("Please input position:");

    while (scanf("%d", &pos) != 1)     {         printf("Input error!!!\n");         printf("Please input again:");         cleanBuffer();     }

    if (pos > getLinkListSize() || pos <= 0)

    {         return 0;     }

    front = moveToTag(pos - 1);

    current = moveToTag(pos);     rear = moveToTag(pos+1);

    front->next = rear;

        free(current);

    return 1;

}

DATA_TYPE findElementByPostion()

{     int pos = 0;     Pointer current = NULL;     printf("Please input position:");

    while (scanf("%d", &pos) != 1)

    {         printf("Input error!!!\n");         printf("Please input again:");         cleanBuffer();     }

    if (pos > getLinkListSize() || pos <= 0)

    {         return -1;     }

    current = moveToTag(pos);

    return current->data;

}

void frontToBack(Pointer tail) {     Pointer current = NULL;     while (1)     {         current = (Pointer)malloc(sizeof(LinkList));         printf("Please input element:");         while (scanf("%d", &current->data) != 1)         {             printf("Input error!!!\n");             printf("Please input again:");             cleanBuffer();         }

        if (current->data == -1)

        {             break;         }

        current->next = NULL;

        tail->next = current;         tail = current;     } }

void backToFront(Pointer tail)

{     Pointer current = NULL;     while (1)     {         current = (Pointer)malloc(sizeof(LinkList));         printf("Please input element:");         while (scanf("%d", &current->data) != 1)         {             printf("Input error!!!\n");             printf("Please input again:");             cleanBuffer();         }         if (current->data == -1)         {             break;         }         current->next = tail->next;         tail->next = current;     } }