（C）学生成绩管理系统

#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();
    //清屏未实现
    system("clear");
        
    FILE *file;
    file=fopen("/Users/5000/Desktop/C:OC作业/Final Project/achievement.txt", "r+");
    struct Student aStudent;
    if (fread(&aStudent, sizeof(struct Student), 1, file)==0) {
        creatDataBace();
    }
    fclose(file);
    //清屏未实现
    
    selectServe();
    
    return 0;
}

void start()
{
    int land;
    printf("1.注册
2.登陆
");
    scanf("%d",&land);
    if (land==1) {
        logon();
    }else
    {
        if (land==2)
            inputNameAndPassword();
        else
        {
            printf("输入有误，请重新选择
");
            start();
        }
     }
}

void logon()
{
    UserInfo userInput;
    printf("
------------------注册用户------------------");
    printf("
请输入注册用户名：");
    scanf("%s",userInput.userName);
    printf("请输入密码：");
    scanf("%s",userInput.userPassword);
    FILE *fp;
    if((fp=fopen("/Users/5000/Desktop/C:OC作业/Final Project/user_password.txt", "a+"))==NULL)
    {
        printf("注册失败！");
        exit(0);
    }
    if ((fwrite(&userInput, sizeof(UserInfo), 1, fp))!=1) {
        printf("注册失败！");
        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作业/Final Project/user_password.txt", "r"))==NULL)
    {
        printf("登陆失败！");
        exit(0);
    }
    
    while(fread(&userBase[i], sizeof(UserInfo), 1, fp)!=0)
        i++;
    count=i;
    fclose(fp);
    
    printf("
------------------用户登陆------------------
");
    while (1)
    {
        printf("用户名：");
        scanf("%s",userInput.userName);
        printf("密码：");
        scanf("%s",userInput.userPassword); //密码用星号代替未实现
        
        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("
用户名或密码输入错误，请重新输入（还有 %d 次机会）：
",3-chance);
        chance++;
        if (chance>=4) {
            printf("
尝试超出次数！退出程序。");
            exit(0);
        }
    }
}

void selectServe()
{
    int serveNumber;
    printf("
------------------操作菜单------------------");
    printf("
1.查询学生成绩
2.添加学生成绩
3.删除学生成绩
4.修改学生成绩
5.查看成绩排名
");
    printf("
请选择您需要的操作(输入序号选择，输入其它退出程序）:");
    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("
 ^^ 再见.....");
}

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作业/Final Project/achievement.txt", "r"))==NULL)
    {
        printf("打开文件错误！");
        exit(0);
    }
    
    for (i=0;fread(&student[i], sizeof(struct Student), 1, fp)!=0;i++);
    count=i;
    fclose(fp);
    
    printf("
------------------初始化数据库------------------");
    i=0;
    while (1) {
        printf("
请输入学生的基本信息:
");
        do
        {
            printf("第 %d 个学生的ID号：",i+1);
            scanf("%s",student[i].id);
            
            for (k=i-1; k>=0; k--) {
                if(strcmp(student[i].id, student[k].id)==0)
                {
                    printf("
ID号已存在，请重新输入
");
                    flag=1;
                    break;
                }
            }
            
            for (k=0; k<count; k++) {
                if(strcmp(student[i].id, student[k].id)==0)
                {
                    printf("
ID号在整个数据库中已存在，请重新输入
");
                    flag=1;
                    break;
                }
            }
        }while(flag);
        
        do
        {
            flag=0;
            printf("学生名称：");
            scanf("%s",student[i].name);
        }while (flag);
        
        do
        {
            flag=0;
            printf("学生成绩：");
            scanf("%d",&student[i].score);
            if (student[i].score>100||student[i].score<0) {
                flag=1;
                continue;
            }
        }while (flag);
        
        i++;
        m++;
        printf("
是否继续创建学生成绩信息？输入'y'或'Y'继续，输入其它进入下一步：");
        getchar();
        scanf("%c",&ch);
        if (ch!='Y'&&ch!='y')
            break;
    }
    
    
    if((fp=fopen("/Users/5000/Desktop/C:OC作业/Final Project/achievement.txt", "a"))==NULL)
    {
        printf("打开文件错误！");
        exit(0);
    }
    
    for (i=0; i<m; i++) {
        if (fwrite(&student[i], sizeof(struct Student), 1, fp)!=1)
            printf("数据保存失败");
    }
    
    fclose(fp);
}

void checkAchievement()
{
    struct Student student;
    char id[4];
    FILE *fp;
    
    printf("
------------------查询学生成绩------------------
");
    printf("请输入需要查询的学生ID：");
    scanf("%s",id);
    while (1)
    {
        if ((fp=fopen("/Users/5000/Desktop/C:OC作业/Final Project/achievement.txt","r"))==NULL)
        {
            printf("打开文件错误！");
            selectServe();
        }
        
        while (fread(&student, sizeof(struct Student), 1, fp)!=0) {
            if (strcmp(id,student.id)==0) {
                printf("ID:%s  姓名:%s  分数:%d
",student.id,student.name,student.score);
                break;
            }
        }

        if (strcmp(id,student.id)!=0)
            printf("没查找到ID为 %s 的学生信息。
",id);
        
        printf("
请输入需要查询的学生ID（输入n返回操作菜单）：");
        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作业/Final Project/achievement.txt", "r"))==NULL)
    {
        printf("打开文件错误！");
        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作业/Final Project/achievement.txt", "a+"))==NULL)
    {
        printf("打开文件错误！");
        selectServe();
    }
    
    printf("
------------------添加学生成绩------------------");
    while (1)
    {
        int flag;
        do {
            flag=0;
            printf("
请输入需要添加的学生ID：");
            scanf("%s",student[count].id);
            for (int k=0; k<count; k++) {
                if(strcmp(student[count].id, student[k].id)==0)
                {
                    printf("ID号在数据库中已存在，请重新输入。
");
                    flag=1;
                    break;
                }
            }
        } while (flag);
        printf("请输入需要添加的学生姓名：");
        scanf("%s",student[count].name);
        printf("请输入需要添加的学生分数：");
        scanf("%d",&student[count].score);
        if (fwrite(&student[count], sizeof(struct Student), 1, fp)!=1) {
            printf("添加失败！");
        }
        printf("添加成功！
");
        printf("
是否继续添加学生成绩信息？输入y继续，输入其它返回操作菜单：");
        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("
------------------删除学生成绩------------------");
    
    if ((infile=fopen("/Users/5000/Desktop/C:OC作业/Final Project/achievement.txt","r"))==NULL)
    {
        printf("打开文件错误！");
        selectServe();
    }
    
    while (fread(&students[i], sizeof(struct Student), 1, infile)!=0) i++;
    count=i;
    fclose(infile);
    
    printf("
请输入需要删除的学生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("没查找到ID为 %s 的学生信息。",id);
        else
        {
            printf("确认要删除ID为 %s 的学生信息吗？（y确定 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作业/Final Project/temp.txt","w+");
                for (i=0; i<count; i++) {
                    if(fwrite(&students[i], sizeof(struct Student), 1, outfile)!=1)
                    {
                        printf("删除失败！");
                        selectServe();
                    }
                }
                fclose(outfile);
            }
            printf("删除成功！
");
        }
        
        printf("
请输入需要删除的学生ID（输入n返回操作菜单）：");
        scanf("%s",id);
        
        if (strcmp(id,"n")==0||strcmp(id,"N")==0) {
            /*其实用w打开原来文件就可以直接写入原来的文件，w打开会清空原来文件的内容*/
            unlink("/Users/5000/Desktop/C:OC作业/Final Project/achievement.txt");//#include <unistd.h>
            rename( "/Users/5000/Desktop/C:OC作业/Final Project/temp.txt","/Users/5000/Desktop/C:OC作业/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作业/Final Project/achievement.txt","r"))==NULL)
    {
        printf("打开文件错误！");
        selectServe();
    }
    while (fread(&students[i], sizeof(struct Student), 1, fp)!=0) i++;
    count=i;
    fclose(fp);
    
    printf("
------------------学生成绩排名------------------
");
    while (1)
    {
        printf("请输入需要修改成绩的学生ID：");
        scanf("%s",id);


        for (i=0;i<count;i++) {
            if (strcmp(id,students[i].id)==0) {
                printf("ID为 %s 的%s同学，分数为:%d
",students[i].id,students[i].name,students[i].score);
                printf("更改%s同学的分数值为：",students[i].name);
                scanf("%d",&score);
                students[i].score=score;
                flag=0;
                break;
            }
        }
        
        if (flag)
            printf("没查找到ID为 %s 的学生信息。
",id);
        
        if ((fp=fopen("/Users/5000/Desktop/C:OC作业/Final Project/achievement.txt","w+"))==NULL)
        {
            printf("打开文件错误！");
            selectServe();
        }
        for (i=0; i<count; i++) {
            if(fwrite(&students[i], sizeof(struct Student), 1, fp)!=1)
            {
                printf("修改失败！");
                selectServe();
            }
        }
        
        printf("
是否继续查询学生成绩信息？输入'y'或'Y'继续，输入其它返回操作菜单：");
        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作业/Final Project/achievement.txt","r"))==NULL)
    {
        printf("打开文件错误！");
        selectServe();
    }
    
    while (fread(&students[i], sizeof(struct Student), 1, fp)!=0) i++;
    fclose(fp);
    count=i;
    
    printf("
------------------学生成绩排名------------------
");
    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
"); //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
",students[i].score);
    }
    
    printf("
输入任意键返回操作菜单：");
    getchar(); //接收选择操作4时输入的回车
    scanf("%c",&ch);
    selectServe();
    
}

运行截图：