Data_Structure/作業/unit4/dlist.c

/* file name: dList.c */
/* 雙向鍵結串列的加入與刪除 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void init_f(void);     /* 初始化串列，建立一空節點為 head */
void insert_f(void);   /* 插入函數 */
void sort_f(void);     /* 排序函數 */
void delete_f(void);   /* 刪除函數 */
void display_f(void);  /* 輸出函數 */
void modify_f(void);   /* 修改函數 */
void flushBuffer(void);

struct Student {
    char name[20];         /* 姓名 */
    int score;             /* 分數 */
    struct Student *llink;  /* 節點左鏈結 */
    struct Student *rlink;  /* 節點右鏈結 */
};
struct Student *ptr, *head, *tail, *current, *prev, *temp;

int main(void)
{
    char option1;

    init_f();
    while(1) {
        printf("\n雙向鏈結串列的運作選單\n");
        printf("************\n");
        printf("   1.insert\n");
        printf("   2.delete\n");
        printf("   3.display\n");
        printf("   4.modify\n");
        printf("   5.quit\n");
        printf("*************\n");
        printf("請輸入選項(1-5): ");
        option1 = getchar();
        flushBuffer();
        switch (option1) {
            case '1':
                insert_f();
                break;
            case '2':
                delete_f();
                break;
            case '3':
                display_f();
                break;
            case '4':
                modify_f();
                break;
            case '5':
                printf("\n程式結束\n");
                exit(0);
        }
    }
    return 0;
}

void init_f(void)  /* 設一個 head，將左右鏈結皆指向本身 */
{
    ptr = (struct Student *) malloc(sizeof(struct Student));
    strcpy(ptr->name, "0");
    ptr->llink = ptr;
    ptr->rlink = ptr;
    head = ptr;
    tail = ptr;
}

void insert_f(void)
{
    ptr = (struct Student *) malloc(sizeof(struct Student));
    printf("\n 姓名: ");
    scanf("%s", ptr->name);
    printf(" 成績: ");
    scanf("%d", &ptr->score);
    flushBuffer();
    
    /* 以分數高低排列 */
    prev = head;
    current = head->rlink;
    while (current != head && current->score > ptr->score) {
        prev = current;
        current = current->rlink;
    }
    ptr->rlink = current;
    ptr->llink = prev;
    prev->rlink = ptr;
    current->llink = ptr;
}

void delete_f(void)
{
    char del_name[20];
    printf("\n 欲刪除姓名: ");
    scanf("%s", del_name);
    flushBuffer();
    prev = head;
    current = head->rlink;
    while (current != head && strcmp(del_name, current->name) != 0) {
        prev = current;
        current = current->rlink;
    }
    if (current != head) {
        prev->rlink = current->rlink;
        current->rlink->llink = prev;
        printf(" %s 已被刪除\n", del_name);
        free(current);
    }
    else  /* 找不到資料則顯示錯誤 */
        printf(" %s 不在串列中\n", del_name);
}

void modify_f(void)
{
    char n_temp[20];
    printf("\n 欲修改的姓名: ");
    scanf("%s", n_temp);
    prev = head;
    current = head->rlink;
    while (current != head && strcmp(n_temp, current->name)) {
        prev = current;
        current = current->rlink;
    }
    if (current == head) {
        printf(" %s 沒有在串列中\n", n_temp);
    }
    else {
        printf(" ******************\n");
        printf("  姓名 : %s\n", current->name);
        printf("  分數: %d\n", current->score);
        printf(" ******************\n");
        printf(" 請輸入新的分數: ");
        scanf("%d", &current->score);
        flushBuffer();
        printf(" %s 已被修改\n", n_temp);
        //將修改的節點加入於適當的位置
        //先將 current 的節點指定給 temp，並重新調整左、右節點
        temp = current;
        prev->rlink = current->rlink;
        current->rlink->llink = prev;
        //再將 temp 節點加入於串列中
        /* 以分數高低排列 */
        prev = head;
        current = head->rlink;
        while (current != head && current->score > temp->score) {
            prev = current;
            current = current->rlink;
        }
        temp->rlink = current;
        temp->llink = prev;
        prev->rlink = temp;
        current->llink = temp;
    }
}

void display_f(void)
{
    int count = 0;
    if (head->rlink == head) {
        printf("\n 串列無資料\n");
    }
    else {
        printf("\n");
        printf("  NAME           SCORE\n");
        printf(" ----------------------\n");
        current = head->rlink;
        while (current != head) {
            printf("  %-15s %3d\n", current->name, current->score);
            count++;
            current = current->rlink;
        }
        printf(" ----------------------\n");
        printf(" 總共有 %d 筆資料\n", count);
    }
}

void flushBuffer(void)
{
    while(getchar() != '\n')
        continue;
}