308 lines
7.9 KiB
C
308 lines
7.9 KiB
C
/* file name: binarySearchTree.c */
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/* 利用二元搜尋樹處理資料－載入、儲存、新增、刪除、修改、輸出 */
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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/* 定義student結構 */
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struct student {
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char name[20]; /* 學生姓名 */
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int score; /* 學生成績 */
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struct student *llink; /* 左子鏈結 */
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struct student *rlink; /* 右子鏈結 */
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};
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void insert_f(void); /* 新增函數 */
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void delete_f(void); /* 刪除函數 */
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void modify_f(void); /* 修改函數 */
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void show_f(void); /* 輸出函數 */
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void process(char [], int); /* 將資料加入二元搜尋樹 */
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void removing(char []); /* 將資料從二元搜尋樹中移除 */
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struct student *replace(struct student *); /* 尋找替代節點 */
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void connecting(struct student *, char); /* 調整鏈結 */
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void inorder(struct student *); /* 資料以中序法輸出 */
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void flushBuffer(void);
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struct student *search(char []); /* 搜尋節點 */
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struct student *search_re_r(struct student *); /* 搜尋右子樹替代節點 */
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struct student *search_re_l(struct student *); /* 搜尋左子樹替代節點 */
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struct student *search_p(struct student *); /* 搜尋父節點 */
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struct student *root, *ptr;
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int main(void)
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{
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char option;
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while(1) {
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puts("");
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puts("********************");
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puts(" <1> insert");
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puts(" <2> delete");
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puts(" <3> modify");
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puts(" <4> show");
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puts(" <5> quit");
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puts("********************");
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printf("Enter your choice: ");
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option = getchar();
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flushBuffer();
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printf("\n");
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switch(option) {
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case '1':
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insert_f();
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break;
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case '2':
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delete_f();
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break;
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case '3':
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modify_f();
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break;
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case '4':
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show_f();
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break;
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case '5':
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exit(0);
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default :
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puts("選項錯誤!");
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}
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}
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return 0;
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}
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/* 新增函數，新增一筆新的資料 */
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void insert_f(void)
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{
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char name[20];
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int score;
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puts("=====INSERT DATA=====");
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printf("姓名: ");
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scanf("%s", name);
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printf("分數: ");
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scanf("%d", &score);
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flushBuffer();
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process(name, score);
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}
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/* 刪除函數，將資料從二元搜尋樹中刪除 */
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void delete_f(void)
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{
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char name[20];
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if (root == NULL) {
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puts("二元搜尋樹是空的!");
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return;
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}
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puts("=====DELETE DATA=====");
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printf("請輸入欲刪除的姓名: ");
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scanf("%s", name);
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flushBuffer();
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removing(name);
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}
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/* 修改資料，修改學生成績 */
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void modify_f(void)
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{
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struct student *node;
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char name[20];
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/* 判斷根節點是否為NULL */
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if (root == NULL) {
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puts("二元搜尋樹是空的!");
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return;
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}
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puts("=====MODIFY DATA===== ");
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printf("請輸入欲修改的姓名: ");
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scanf("%s", name);
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flushBuffer();
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if ((node = search(name)) == NULL)
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printf("%s 不在二元搜尋中!\n", name);
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else {
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/* 列出原資料狀況 */
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printf("姓名: %s\n", node->name);
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printf("分數: %d\n\n", node->score);
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printf("請輸入新的分數: ");
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scanf("%d", &node->score);
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flushBuffer();
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printf("%s 已被修改\n", name);
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}
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}
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/* 輸出函數，將資料輸出至螢幕 */
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void show_f(void)
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{
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/* 判斷根節點是否為NULL */
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if (root == NULL) {
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puts("二元搜尋樹是空的!");
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return;
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}
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puts("=====SHOW DATA=====");
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inorder(root); /* 以中序法輸出資料 */
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}
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/* 處理二元搜尋樹，將新增資料加入至二元搜尋樹中 */
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void process(char name[], int score)
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{
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struct student *node, *prev;
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/* 資料已存在則顯示錯誤 */
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if (search(name) != NULL) {
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printf("%s 已存在!\n", name);
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return;
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}
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ptr = (struct student *) malloc(sizeof(struct student));
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strcpy(ptr->name, name);
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ptr->score = score;
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ptr->llink = ptr->rlink = NULL;
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if (root == NULL) /* 當根節點為NULL的狀況 */
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root = ptr;
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else { /* 當根節點不為NULL的狀況 */
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node = root;
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while (node != NULL) { /* 搜尋資料插入點 */
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prev = node;
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if(strcmp(ptr->name, node->name) < 0)
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node = node->llink;
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else
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node = node->rlink;
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}
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if (strcmp(ptr->name, prev->name) < 0)
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prev->llink = ptr;
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else
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prev->rlink = ptr;
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}
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}
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/* 將資料從二元搜尋樹中移除 */
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void removing(char name[])
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{
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struct student *del_node;
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if((del_node = search(name)) == NULL) /* 找不到資料則顯示錯誤 */
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{
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printf("%s 不在此二元搜尋樹中!\n", name);
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return;
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}
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/* 節點不為樹葉節點的狀況 */
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if (del_node->llink != NULL || del_node->rlink != NULL)
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del_node = replace(del_node);
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else /* 節點為樹葉節點的狀況 */
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if(del_node == root)
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root = NULL;
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else
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connecting(del_node, 'n');
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free(del_node); /* 釋放記憶體 */
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printf("%s 已被刪除!\n", name);
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}
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/* 尋找刪除非樹葉節點的替代節點 */
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struct student *replace(struct student *node)
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{
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struct student *re_node;
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/* 當右子樹找不到替代節點，會搜尋左子樹是否存在替代節點 */
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if ((re_node = search_re_r(node->rlink)) == NULL)
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re_node = search_re_l(node->llink);
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if (re_node->rlink != NULL) /* 當替代節點有右子樹存在的狀況 */
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connecting(re_node, 'r');
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else
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if (re_node->llink != NULL) /* 當替代節點有左子樹存在的狀況 */
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connecting(re_node, 'l');
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else /* 當替代節點為樹葉節點的狀況 */
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connecting(re_node, 'n');
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strcpy(node->name, re_node->name);
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node->score = re_node->score;
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return re_node;
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}
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/* 調整二元搜尋樹的鏈結，link 為 r 表示處理右鏈結，為 l 表處理左鏈結，
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為 m 則將鏈結指向 NULL */
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void connecting(struct student *node, char link)
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{
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struct student *parent;
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parent = search_p(node); /* 搜尋父節點 */
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/* 節點為父節點左子樹的狀況 */
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if (strcmp(node->name, parent->name) < 0)
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if(link == 'r') /* link為r */
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parent->llink = node->rlink;
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else /* link為m */
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parent->llink = NULL;
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else /* 節點為父節點右子樹的狀況 */
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if (link == 'l') /* link為l */
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parent->rlink = node->llink;
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else /* link為m */
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parent->rlink = NULL;
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}
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/* 以中序法輸出資料，採遞迴方式 */
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void inorder(struct student *node)
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{
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if(node != NULL) {
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inorder(node->llink);
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printf("%-10s %d\n", node->name, node->score);
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inorder(node->rlink);
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}
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}
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/* 搜尋target所在節點 */
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struct student *search(char target[])
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{
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struct student *node;
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node = root;
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while(node != NULL)
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{
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if (strcmp(target, node->name) == 0)
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return node;
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else
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/* target小於目前節點，往左搜尋 */
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if (strcmp(target, node->name) < 0)
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node = node->llink;
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else /* target大於目前節點，往右搜尋 */
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node = node->rlink;
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}
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return node;
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}
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/* 搜尋右子樹替代節點 */
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struct student *search_re_r(struct student *node)
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{
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struct student *re_node;
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re_node = node;
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while (re_node != NULL && re_node->llink != NULL)
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re_node = re_node->llink;
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return re_node;
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}
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/* 搜尋左子樹替代節點 */
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struct student *search_re_l(struct student *node)
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{
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struct student *re_node;
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re_node = node;
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while (re_node != NULL && re_node->rlink != NULL)
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re_node = re_node->rlink;
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return re_node;
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}
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/* 搜尋node的父節點 */
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struct student *search_p(struct student *node)
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{
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struct student *parent;
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parent = root;
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while (parent != NULL) {
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if (strcmp(node->name, parent->name) < 0) {
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if (strcmp(node->name, parent->llink->name) == 0)
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return parent;
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else
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parent = parent->llink;
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}
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else {
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if (strcmp(node->name, parent->rlink->name) == 0)
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return parent;
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else
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parent = parent->rlink;
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}
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}
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return NULL;
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}
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void flushBuffer()
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{
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while (getchar() != '\n')
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continue;
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}
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