（C）學生成績管理系統

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

struct Student
{
    char id[4];
    char name[10];
    int score;
};

typedef struct User
{
    char userName[20];
    char userPassword[10];
}UserInfo;

void inputNameAndPassword();
void logon();
void creatDataBace();
void selectServe();
void checkAchievement();
void addAchievement();
void delectAchievement();
void changeAchievement();
void sortAchievement();
void start();

int main(int argc, const char * argv[])
{
    start();
    //清屏未實現
    system("clear");
        
    FILE *file;
    file=fopen("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt", "r+");
    struct Student aStudent;
    if (fread(&aStudent, sizeof(struct Student), 1, file)==0) {
        creatDataBace();
    }
    fclose(file);
    //清屏未實現
    
    selectServe();
    
    return 0;
}

void start()
{
    int land;
    printf("1.注冊\n2.登陸\n");
    scanf("%d",&land);
    if (land==1) {
        logon();
    }else
    {
        if (land==2)
            inputNameAndPassword();
        else
        {
            printf("輸入有誤，請重新選擇\n");
            start();
        }
     }
}

void logon()
{
    UserInfo userInput;
    printf("\n------------------注冊用戶------------------");
    printf("\n請輸入注冊用戶名：");
    scanf("%s",userInput.userName);
    printf("請輸入密碼：");
    scanf("%s",userInput.userPassword);
    FILE *fp;
    if((fp=fopen("/Users/5000/Desktop/C:OC作業/Final Project/user_password.txt", "a+"))==NULL)
    {
        printf("注冊失敗！");
        exit(0);
    }
    if ((fwrite(&userInput, sizeof(UserInfo), 1, fp))!=1) {
        printf("注冊失敗！");
        exit(0);
    }
    fclose(fp);
    inputNameAndPassword();
}

void inputNameAndPassword()
{
    UserInfo userInput,userBase[50];
    int i=0,count=0,chance=0;
    
    FILE *fp;
    if((fp=fopen("/Users/5000/Desktop/C:OC作業/Final Project/user_password.txt", "r"))==NULL)
    {
        printf("登陸失敗！");
        exit(0);
    }
    
    while(fread(&userBase[i], sizeof(UserInfo), 1, fp)!=0)
        i++;
    count=i;
    fclose(fp);
    
    printf("\n------------------用戶登陸------------------\n");
    while (1)
    {
        printf("用戶名：");
        scanf("%s",userInput.userName);
        printf("密碼：");
        scanf("%s",userInput.userPassword); //密碼用星號代替未實現
        
        for (i=0; i<count; i++) {
            if((strcmp(userInput.userName, userBase[i].userName)==0)&&(strcmp(userInput.userPassword, userBase[i].userPassword)==0))
                return;
        }
        if (chance!=3)
            printf("\n用戶名或密碼輸入錯誤，請重新輸入（還有 %d 次機會）：\n",3-chance);
        chance++;
        if (chance>=4) {
            printf("\n嘗試超出次數！退出程序。");
            exit(0);
        }
    }
}

void selectServe()
{
    int serveNumber;
    printf("\n------------------操作菜單------------------");
    printf("\n1.查詢學生成績\n2.添加學生成績\n3.刪除學生成績\n4.修改學生成績\n5.查看成績排名\n");
    printf("\n請選擇您需要的操作(輸入序號選擇，輸入其它退出程序）:");
    scanf("%d",&serveNumber);
    switch (serveNumber) {
        case 1:
            checkAchievement();
            break;
        case 2:
            addAchievement();
            break;
        case 3:
            delectAchievement();
            break;
        case 4:
            changeAchievement();
            break;
        case 5:
            sortAchievement();
            break;
        default:
            break;
    }
    printf("\n ^^ 再見.....");
}

void creatDataBace()
{
    FILE *fp;
    struct Student student[100];
    int flag=0;
    int i=0;
    int k=0;
    int count=0;
    int m=0;
    char ch;
    
    if((fp=fopen("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt", "r"))==NULL)
    {
        printf("打開文件錯誤！");
        exit(0);
    }
    
    for (i=0;fread(&student[i], sizeof(struct Student), 1, fp)!=0;i++);
    count=i;
    fclose(fp);
    
    printf("\n------------------初始化數據庫------------------");
    i=0;
    while (1) {
        printf("\n請輸入學生的基本信息:\n");
        do
        {
            printf("第 %d 個學生的ID號：",i+1);
            scanf("%s",student[i].id);
            
            for (k=i-1; k>=0; k--) {
                if(strcmp(student[i].id, student[k].id)==0)
                {
                    printf("\nID號已存在，請重新輸入\n");
                    flag=1;
                    break;
                }
            }
            
            for (k=0; k<count; k++) {
                if(strcmp(student[i].id, student[k].id)==0)
                {
                    printf("\nID號在整個數據庫中已存在，請重新輸入\n");
                    flag=1;
                    break;
                }
            }
        }while(flag);
        
        do
        {
            flag=0;
            printf("學生名稱：");
            scanf("%s",student[i].name);
        }while (flag);
        
        do
        {
            flag=0;
            printf("學生成績：");
            scanf("%d",&student[i].score);
            if (student[i].score>100||student[i].score<0) {
                flag=1;
                continue;
            }
        }while (flag);
        
        i++;
        m++;
        printf("\n是否繼續創建學生成績信息？輸入'y'或'Y'繼續，輸入其它進入下一步：");
        getchar();
        scanf("%c",&ch);
        if (ch!='Y'&&ch!='y')
            break;
    }
    
    
    if((fp=fopen("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt", "a"))==NULL)
    {
        printf("打開文件錯誤！");
        exit(0);
    }
    
    for (i=0; i<m; i++) {
        if (fwrite(&student[i], sizeof(struct Student), 1, fp)!=1)
            printf("數據保存失敗");
    }
    
    fclose(fp);
}

void checkAchievement()
{
    struct Student student;
    char id[4];
    FILE *fp;
    
    printf("\n------------------查詢學生成績------------------\n");
    printf("請輸入需要查詢的學生ID：");
    scanf("%s",id);
    while (1)
    {
        if ((fp=fopen("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt","r"))==NULL)
        {
            printf("打開文件錯誤！");
            selectServe();
        }
        
        while (fread(&student, sizeof(struct Student), 1, fp)!=0) {
            if (strcmp(id,student.id)==0) {
                printf("ID:%s  姓名:%s  分數:%d\n",student.id,student.name,student.score);
                break;
            }
        }

        if (strcmp(id,student.id)!=0)
            printf("沒查找到ID為 %s 的學生信息。\n",id);
        
        printf("\n請輸入需要查詢的學生ID（輸入n返回操作菜單）：");
        scanf("%s",id);
        if (strcmp(id,"n")==0||strcmp(id,"N")==0) {
            fclose(fp);
            selectServe();
        }
        fclose(fp);
    }
}

void addAchievement()
{
    FILE *fp;
    struct Student student[100];
    int i=0;
    int count=0;
    char ch;
    
    if((fp=fopen("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt", "r"))==NULL)
    {
        printf("打開文件錯誤！");
        selectServe();
    }
    
    for (i=0;fread(&student[i], sizeof(struct Student), 1, fp)!=0;i++);
    count=i;
    fclose(fp);
    
    if((fp=fopen("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt", "a+"))==NULL)
    {
        printf("打開文件錯誤！");
        selectServe();
    }
    
    printf("\n------------------添加學生成績------------------");
    while (1)
    {
        int flag;
        do {
            flag=0;
            printf("\n請輸入需要添加的學生ID：");
            scanf("%s",student[count].id);
            for (int k=0; k<count; k++) {
                if(strcmp(student[count].id, student[k].id)==0)
                {
                    printf("ID號在數據庫中已存在，請重新輸入。\n");
                    flag=1;
                    break;
                }
            }
        } while (flag);
        printf("請輸入需要添加的學生姓名：");
        scanf("%s",student[count].name);
        printf("請輸入需要添加的學生分數：");
        scanf("%d",&student[count].score);
        if (fwrite(&student[count], sizeof(struct Student), 1, fp)!=1) {
            printf("添加失敗！");
        }
        printf("添加成功！\n");
        printf("\n是否繼續添加學生成績信息？輸入y繼續，輸入其它返回操作菜單：");
        getchar();
        scanf("%c",&ch);
        if (ch!='y'&&ch!='Y') {
            fclose(fp);
            selectServe();
        }
        count++;
    }
}

void delectAchievement()
{
    char id[4];
    char sure;
    FILE *infile,*outfile;
    struct Student students[100];
    int i=0,flag=-1,count=0;
    
    
    printf("\n------------------刪除學生成績------------------");
    
    if ((infile=fopen("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt","r"))==NULL)
    {
        printf("打開文件錯誤！");
        selectServe();
    }
    
    while (fread(&students[i], sizeof(struct Student), 1, infile)!=0) i++;
    count=i;
    fclose(infile);
    
    printf("\n請輸入需要刪除的學生ID：");
    scanf("%s",id);
    while (1)
    {
        for (i=0; i<count; i++) {
            if (strcmp(id,students[i].id)==0) {
                flag=i;
                break;
            }
        }
        
        if (flag==-1)
            printf("沒查找到ID為 %s 的學生信息。",id);
        else
        {
            printf("確認要刪除ID為 %s 的學生信息嗎？（y確定 n取消）",id);
            getchar();
            scanf("%c",&sure);
            if (sure=='y')
            {
                for (i=flag; i<count-1; i++) {
                    students[i]=students[i+1];
                }
                count--;
            
                outfile=fopen("/Users/5000/Desktop/C:OC作業/Final Project/temp.txt","w+");
                for (i=0; i<count; i++) {
                    if(fwrite(&students[i], sizeof(struct Student), 1, outfile)!=1)
                    {
                        printf("刪除失敗！");
                        selectServe();
                    }
                }
                fclose(outfile);
            }
            printf("刪除成功！\n");
        }
        
        printf("\n請輸入需要刪除的學生ID（輸入n返回操作菜單）：");
        scanf("%s",id);
        
        if (strcmp(id,"n")==0||strcmp(id,"N")==0) {
            /*其實用w打開原來文件就可以直接寫入原來的文件，w打開會清空原來文件的內容*/
            unlink("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt");//#include <unistd.h>
            rename( "/Users/5000/Desktop/C:OC作業/Final Project/temp.txt","/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt");//#include <unistd.h>
            selectServe();
        }
    } 
}

void changeAchievement()
{
    FILE *fp;
    char id[4],ch;
    int score=0,count=0,flag=1;
    int i=0;
    struct Student students[100];
    
    if ((fp=fopen("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt","r"))==NULL)
    {
        printf("打開文件錯誤！");
        selectServe();
    }
    while (fread(&students[i], sizeof(struct Student), 1, fp)!=0) i++;
    count=i;
    fclose(fp);
    
    printf("\n------------------學生成績排名------------------\n");
    while (1)
    {
        printf("請輸入需要修改成績的學生ID：");
        scanf("%s",id);


        for (i=0;i<count;i++) {
            if (strcmp(id,students[i].id)==0) {
                printf("ID為 %s 的%s同學，分數為:%d\n",students[i].id,students[i].name,students[i].score);
                printf("更改%s同學的分數值為：",students[i].name);
                scanf("%d",&score);
                students[i].score=score;
                flag=0;
                break;
            }
        }
        
        if (flag)
            printf("沒查找到ID為 %s 的學生信息。\n",id);
        
        if ((fp=fopen("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt","w+"))==NULL)
        {
            printf("打開文件錯誤！");
            selectServe();
        }
        for (i=0; i<count; i++) {
            if(fwrite(&students[i], sizeof(struct Student), 1, fp)!=1)
            {
                printf("修改失敗！");
                selectServe();
            }
        }
        
        printf("\n是否繼續查詢學生成績信息？輸入'y'或'Y'繼續，輸入其它返回操作菜單：");
        getchar();
        scanf("%c",&ch);
        if (ch!='y'&&ch!='Y') {
            fclose(fp);
            selectServe();
        }
    }
}

void sortAchievement()
{
    char ch;
    FILE *fp;
    struct Student students[100],temp;
    int i=0,j=0,count=0;
    
    if ((fp=fopen("/Users/5000/Desktop/C:OC作業/Final Project/achievement.txt","r"))==NULL)
    {
        printf("打開文件錯誤！");
        selectServe();
    }
    
    while (fread(&students[i], sizeof(struct Student), 1, fp)!=0) i++;
    fclose(fp);
    count=i;
    
    printf("\n------------------學生成績排名------------------\n");
    for(i=0;i<count-1;i++)
        for(j=0;j<count-1-i;j++)
        {
            if (students[j].score<students[j+1].score) {
                temp=students[j];
                students[j]=students[j+1];
                students[j+1]=temp;
            }
        }
    printf("ID    Name      Score\n"); //Id****Name******Score
    for (i=0; i<count; i++) {
        printf("%s",students[i].id);
        for (j=0; j<6-strlen(students[i].id); j++) 
            printf(" ");
        
        printf("%s",students[i].name);
        for (j=0; j<10-strlen(students[i].name); j++) 
            printf(" ");
            
        printf("%d\n",students[i].score);
    }
    
    printf("\n輸入任意鍵返回操作菜單：");
    getchar(); //接收選擇操作4時輸入的回車
    scanf("%c",&ch);
    selectServe();
    
}

運行截圖：