鏈表-簡易學生成績管理

原文：http://blog.csdn.net/bdmh/article/details/6112631

看到論壇裏總有學生在尋求鏈表實現學生成績管理的帖子，動手寫一個，也算學習，雖然功能很少，以前還真沒寫過完整的，寫的比較粗糙，比較簡單，不合適的地方歡迎指正。

 

LinkTable.h

class StudentInfo
{
public:
    char code[6];
    float chinesescore;
    float mathscore;
    StudentInfo* next;
    StudentInfo* prior;
};

//添加學生信息，如果prior爲NULL，則newinfo爲頭結點
StudentInfo* AddInfo(StudentInfo* prior,StudentInfo* newinfo);
//根據編號刪除學生信息
bool DelStudentInfo(char* code,StudentInfo*& pHead);
//根據編號查找學生信息
StudentInfo* FindStudentInfoByCode(char* code,StudentInfo* pHead);
//修改學生成績信息
void ModifyStudentInfo(StudentInfo* p);
//從頭結點開始打印學生信息
void PrintStudentInfo(StudentInfo* pHead);
//對指定的節點輸入學生信息
void InputInfo(StudentInfo* pInfo);
//獲取最後一個節點
StudentInfo* GetLastStudentInfo(StudentInfo* pHead);
//保存鏈表到文件，順序保存
void SaveStudentInfoToFile(char* filename,StudentInfo* pHead);
//從文件中讀取鏈表
void LoadStudentInfoFromFile(char* filename,StudentInfo*& pHead);
//操作提示
void ShowOperateInfo(void);

 

LinkTable.cpp

#include "LinkTable.h"
#include <stdio.h>
#include <string.h>

//添加學生信息，如果prior爲NULL，則newinfo爲頭結點
StudentInfo* AddInfo(StudentInfo* prior,StudentInfo* newinfo)
{
    if (!prior)
    {
        newinfo->next = NULL;
        newinfo->prior = NULL;
    }
    else
    {
        prior->next = newinfo;
        newinfo->prior = prior;
        newinfo->next = NULL;
    }
    memset(newinfo->code,0,sizeof(newinfo->code));
    InputInfo(newinfo);
    return newinfo;
}

//根據編號刪除學生信息
bool DelStudentInfo(char* code,StudentInfo*& pHead)
{
    StudentInfo* pDel = FindStudentInfoByCode(code,pHead);
    if (pDel == NULL)
        return false;
    else
    {
        if (pDel == pHead)
            pHead = pDel->next;
        else
        {
            pDel->prior->next = pDel->next;
            if (pDel->next != NULL)
                pDel->next->prior = pDel->prior;
        }
        delete pDel;
        pDel = NULL;
        return true;
    }
}

//根據編號查找學生信息
StudentInfo* FindStudentInfoByCode(char* code,StudentInfo* pHead)
{
    StudentInfo* p = pHead;
    while (p != NULL)
    {
        if (strcmp(p->code,code) == 0)
        {
            return p;
        }
        p = p->next;
    }
    return NULL;
}
//修改學生成績信息
void ModifyStudentInfo(StudentInfo* p)
{
    printf("%s號學生當前信息：語文：%f，數學：%f/n",p->code,p->chinesescore,p->mathscore);
    printf("%s","請輸入修改後的語文成績：");
    scanf("%f",&p->chinesescore);
    printf("%s","請輸入修改後的數學成績：");
    scanf("%f",&p->mathscore);
    printf("修改完畢，%s號學生最新信息：語文：%f，數學：%f/n",p->code,p->chinesescore,p->mathscore);
}

//從頭結點開始打印學生信息
void PrintStudentInfo(StudentInfo* pHead)
{
    StudentInfo* p = pHead;
    while (p!=NULL)
    {
        printf("%s號學生：語文：%f，數學：%f/n",p->code,p->chinesescore,p->mathscore);
        p = p->next;
    }
}

//對指定的節點輸入學生信息
void InputInfo(StudentInfo* pInfo)
{
    printf("%s","請輸入學生編號：");
    scanf("%s",pInfo->code);
    printf("%s","請輸入語文成績：");
    scanf("%f",&pInfo->chinesescore);
    printf("%s","請輸入數學成績：");
    scanf("%f",&pInfo->mathscore);
}

//獲取最後一個節點
StudentInfo* GetLastStudentInfo(StudentInfo* pHead)
{
    if (pHead == NULL)
        return NULL;
    StudentInfo* p = pHead;
    while (p)
    {
        if (p->next == NULL)
            return p;
        p = p->next;
    }
}

//保存鏈表到文件，順序保存
void SaveStudentInfoToFile(char* filename,StudentInfo* pHead)
{
    FILE* f;
    f= fopen(filename,"w");
    StudentInfo* p = pHead;
    while (p)
    {
        fwrite(p->code,sizeof(char),sizeof(p->code),f);
        fwrite(&p->chinesescore,sizeof(float),1,f);
        fwrite(&p->mathscore,sizeof(float),1,f);
        //fwrite("/n",sizeof(char),1,f);
        p=p->next;
    }
    //fwrite("/0",sizeof(char),1,f);
    fclose(f);
}

//從文件中讀取鏈表
void LoadStudentInfoFromFile(char* filename,StudentInfo*& pHead)
{
    FILE* f;
    f= fopen(filename,"r");
    if (f == NULL)
        return;
    fseek(f, 0, SEEK_SET);
    StudentInfo* p = NULL;
    StudentInfo* newp = NULL;
    int c;
    //c = fgetc(f);
    while (!feof(f))
    {
        //因爲不能完全依賴feof判斷文件是否到結尾，所以用fgetc的返回值來判斷，
        //當讀取到結尾時，feof實際並沒有獲得到達結尾的信息，所以這裏用fgetc繼續讀取一個字符，來判斷是否結束
        //如果不是-1（結尾），那麼回退一個文件位置，如果是-1，退出
        c = fgetc(f);
        if (c != -1)
            fseek(f, -1, SEEK_CUR);
        else
            return;
        if (pHead == NULL)
        {
            pHead = new StudentInfo;
            pHead->next = NULL;
            pHead->prior = NULL;
            memset(pHead->code,0,sizeof(pHead->code));
            fread(pHead->code,sizeof(char),sizeof(pHead->code),f);
            fread(&pHead->chinesescore,sizeof(float),1,f);
            fread(&pHead->mathscore,sizeof(float),1,f);
            p = pHead;
        }
        else
        {
            newp = new StudentInfo;
            newp->next = NULL;
            newp->prior = NULL;
            newp->prior = p;
            memset(newp->code,0,sizeof(newp->code));
            fread(newp->code,sizeof(char),sizeof(newp->code),f);
            fread(&newp->chinesescore,sizeof(float),1,f);
            fread(&newp->mathscore,sizeof(float),1,f);
            p->next = newp;
            p = newp;
        }

    }
    fclose(f);
}

//操作提示
void ShowOperateInfo(void)
{
    printf("%s/n","1:增加信息");
    printf("%s/n","2:刪除信息");
    printf("%s/n","3:查找信息");
    printf("%s/n","4:修改信息");
    printf("%s/n","5:保存信息");
    printf("%s/n","9:打印信息");
    printf("%s/n","0:結束");
}

 

Main方法

#include "LinkTable.h"

int main()
{
    ShowOperateInfo();
    int i;
    //curInfo當前節點，用來添加節點用
    StudentInfo* curInfo = new StudentInfo;
    StudentInfo* pHead = NULL;
    LoadStudentInfoFromFile("e://link.txt",pHead);
    //將curInfo指向最後一個節點
    if (pHead != NULL)
        curInfo = GetLastStudentInfo(pHead);
    char code[10]={0};
    while (true)
    {
        printf("%s","請輸入操作號：");
        scanf("%d",&i);
        switch (i)
        {
            //退出
        case 0:
            exit(0);
            //添加
        case 1:
            if (pHead == NULL)
            {
                pHead = new StudentInfo;
                curInfo = pHead = AddInfo(NULL,pHead);
            }
            else
            {
                StudentInfo* newInfo = new StudentInfo;
                curInfo = AddInfo(curInfo,newInfo);
            }
            break;
            //刪除
        case 2:
            printf("%s","請輸入要刪除的學生編號：");
            scanf("%s",code);
            DelStudentInfo(code,pHead);
            curInfo = GetLastStudentInfo(pHead);
            break;
            //查找
        case 3:
            printf("%s/n","請輸入要查找的學生編號：");
            scanf("%s",code);
            {
                StudentInfo* p = FindStudentInfoByCode(code,pHead);
                if (p == NULL)
                    printf("編號%s不存在",code);
                else
                {
                    printf("%s號學生：語文：%f，數學：%f/n",p->code,p->chinesescore,p->mathscore);
                }
            }
            break;
            //修改
        case 4:
            printf("%s/n","請輸入要修改的學生編號：");
            scanf("%s",code);
            {
                StudentInfo* p = FindStudentInfoByCode(code,pHead);
                if (p == NULL)
                    printf("編號%s不存在",code);
                else
                {
                    ModifyStudentInfo(p);
                }
            }
            break;
        case 5:
            SaveStudentInfoToFile("e://link.txt",pHead);
            break;
            //打印
        case 9:
            PrintStudentInfo(pHead);
            break;
        default:
            exit(0);
        }
    }
}

 

運行結果：