C 语言学生管理系统

#include<stdio.h>#include<string.h>#include<ctype.h>#include<stdlib.h>#define N 10000typedef struct student{    char ID[10];                       /*学号*/    char name [20];                    /*姓名*/    char sex;                          /*性别*/    double score[5];                   /*五门课的成绩*/    double total;                      /*总成绩*/    double avg;                        /*平均成绩*/}STU;
void display(void);                         /*显示主菜单*/void load(STU stu[],int *nPtr);            /*把学生信息加载到内存*/void save(STU stu[],int n);                 /*大将数据保存到磁盘*/void sort (STU stu[],int n);                /*排序*/void InputRecord(STU st1[],int i);          /*输入一条记录*/void find (STU stu[],int n);                /*查找*/void del (STU stu[],int *nPtr);             /*删除*/void add (STU stu[],int *nPtr);             /*添加一条记录*/void edit(STU stu[],int n);                 /*修改一条记录*/void DeleteAll (STU stu[],int *nPtr);       /*删除所有信息*/void DeleteRecord(STU stu[],int *nPtr);      /*删除一条记录*/int  FindByNum (STU stu[],int n,char *str);       /*按学号查找*/void output (STU stu[],int n);              /*输出所有信息*/void PrintRecord(STU *sPtr);                /*输出一条记录*/int ScoreAsc( STU a,STU b); 				/*按成绩升厅排序规则,若a,b逆序,返回1*/int ScoreDes (STU a, STU b);				/*按成绩降序排序规则,若a, b逆序，返回1*/int NameAsc(STU a, STU b);					/*按姓名升序排序规则,若a,b逆序，返回一个正整数*/

int main(){    STU stu[N];    int n;    int select;
    load(stu,&n);
    while (1)    {        display();        scanf("%d",&select);        switch(select)        {            case 1:             /*添加*/                add(stu, &n);break;            case 2:             /*修改*/                edit (stu,n); break;            case 3:             /*排序*/                sort(stu, n); break;            case 4:             /*查找*/                find(stu, n); break;            case 5:             /*删除*/                del(stu, &n); break;            case 6:             /*输出*/                output(stu,n);break;                  case 7:             /*退出*/                return 0;        }    }    return 0; }
/*按成绩升厅排序规则,若a,b逆序,返回1*/int ScoreAsc( STU a,STU b){    return a.total > b.total ? 1:-1;}/*按成绩降序排序规则,若a, b逆序，返回1*/int ScoreDes (STU a, STU b){    return a.total<b.total ? 1:-1;}/*按姓名升序排序规则,若a,b逆序，返回一个正整数*/int NameAsc(STU a, STU b){    return strcmp( a.name, b. name);}
void display(void)                         /*显示主菜单*/{    system("cls");    printf("欢迎使用本学生成绩管理系统\n");    printf("说明:在本系统中欲执行某功能请输入相应数字\n");    printf("1.添加\n");    printf("2.修改\n");    printf("3.排序\n");    printf("4.查找\n");    printf("5.删除\n");    printf("6.输出\n");    printf("7.退出\n");}void load(STU stu[],int *nPtr) 				/*把学生信息加载到内存*/   {    FILE *fp;    STU ex;    int i=0;    if(((fp = fopen("sutdent txt", "r")))==NULL)    {        *nPtr =0;        return;    }    while(fscanf(fp,"%s %s %c %lf %lf %lf %lf %lf %lf %lf\n",ex.ID,ex.name,&ex.sex,&ex.score[0],&ex.score[1],&ex.score[2] ,&ex.score[3] ,&ex.score[4] ,&ex.total,&ex.avg)!=EOF)    {    strcpy(stu[i].ID,ex.ID);    strcpy(stu[i].name,ex.name);    stu[i].sex=ex.sex;    stu[i].score[0]=ex.score[0];     stu[i].score[1]=ex.score[1];     stu[i].score[2]=ex.score[2];     stu[i].score[3]=ex.score[3];     stu[i].score[4]=ex.score[4];     stu[i].total=ex.total;    stu[i].avg=ex.avg;    i++;    }    *nPtr=i;    fclose(fp);/*关闭文件*/}void save(STU stu[],int n)                 /*大将数据保存到磁盘*/{    FILE *fp;    int i;    if((fp = fopen("sutdent txt", "wb"))==NULL)    {        printf("打开文件失败\n");        exit(0);    } //    fwrite(stu, n *sizeof(stu[0]),1,fp);    for(i=0;i<n;i++)    fprintf(fp,"%s %s %c % 0lf % 0lf % 0lf % 0lf % 0lf % 0lf % 2lf\n",stu[i].ID,stu[i].name,stu[i].sex,stu[i].score[0],stu[i].score[1],stu[i].score[2] ,stu[i].score[3] ,stu[i].score[4] ,stu[i].total,stu[i].avg);    fclose(fp);}void sort (STU stu[],int n)                /*排序*/{    int select, i,j;    int (*cmp)( STU a, STU b );
    int ScoreAsc( STU a, STU b);    int ScoreDes( STU a, STU b );    int NameAsc( STU a,STU b );
    printf("1.按总分升序排列\n");    printf("2.按总分降序排列\n");    printf("3.按姓名排列\n");      scanf("%d", &select);        switch(select)    {    case 1: cmp =ScoreAsc; break;    case 2: cmp =ScoreDes; break;    case 3: cmp =NameAsc; break;    default: return;    }
    /*按照指定规则,进行比较交换排序*/    for(i =0;i<n-1;i++)        for(j=i+1;j<n;j++)            if((*cmp) (stu[i],stu[j])>0)/*若逆序，cmp返回正数*/                {                    STU temp;                    temp=stu[i];                    stu[i]=stu[j];                    stu[j]=temp;                }    output(stu, n);}void InputRecord(STU stu[],int i)          /*输入一条记录*/{    int j;
    /*输入学号，并验证合法性*/    printf("请输入第%d个学生信息\n", i+1);
    printf("请输入学生学号(学号小于9位数字组成)\n");    scanf("%s",&stu[i].ID);    /*输入姓名*/    printf("请输入学生姓名\n");    scanf("%s",stu[i].name);
    printf("请输入学生性别(f或m f代表女性 m代表男性)\n");    getchar();    scanf("%c",&stu[i].sex);    /*输入5门课程成绩并累加*/    printf("请输入五门课成绩(0~100)\n");    stu[i].total =0;
    for(j = 0;j < 5;j++)    {    	scanf("%lf",&stu[i].score[j]);    	stu[i].total +=stu[i].score[j];	}    /*计算总成绩*/    stu[i].avg=stu[i].total / 5;}void find (STU stu[],int n)                /*查找*/{	int index;    char str[20];    printf("请输入学号:\n");scanf("%s",str);    index = FindByNum (stu, n, str);    if(index >=0)    PrintRecord (&stu [index]);else    printf("该学生信息不存在\n");    system("pause");}void del (STU stu[],int *nPtr)             /*删除*/{ 		int i, index;    char str[20];
    printf("请输入学号:\n");    scanf("%s",str);    index = FindByNum(stu, *nPtr,str);
    if(index <0)    {        printf(" \n该学生信息不存在\n");        return;    }
    for(i =index; i<*nPtr-1;i++)        stu[i]=stu[i+1];        (*nPtr)--;    printf("In 删除成功\n");    save(stu,  *nPtr);/*保存到文件*/}void add (STU stu[],int *nPtr)             /*添加一条记录*/{ 	int i=0;    char sel ='y';    while(sel == 'y')    {        InputRecord(stu,(*nPtr)++);        /*添加第n+1个学生信息*/        printf("是否继续添加(yes--y,no--others) \n");        scanf(" %c", &sel);        save(stu, *nPtr);    }    }void edit(STU stu[], int n)				   /*修改一条记录*/{                  int i, index;     char sel;    char str[20];
    printf("请输入学号:\n");    scanf( "%s", str);
    index = FindByNum(stu, n, str);    if(index<0)    {        printf("该学生信息不存在\n");        return;    }    printf("修改前的原记录如下:\n");    PrintRecord(&stu[index]);        /*修改姓名*/    printf("是否修改姓名?请输入 y or n:\n");    scanf(" %c", &sel);
    if(sel == 'y')    {        printf("请输入姓名:\n");        scanf("%s", stu[index].name);    }        /*修改性别*/    printf("是否修改性别?请输入 y or n\n");    scanf(" %c", &sel);    if(sel == 'y')    {        printf("请输入f or m:\n");        scanf(" %c", &stu[index] .sex);    }        /*修改成绩*/    printf("是否修改成绩?请输入 y or n:\n");    scanf(" %c", &sel);    if(sel == 'y')    {        stu[index].total = 0;        printf("输5门学科成绩:\n");        for(i = 0; i<5;i++)        {	        scanf("%lf", &stu[index] .score[i]);	        stu[index].total = stu[index].total +stu[index] .score[i];	        stu[index].avg=stu[index] .total / 5;        }    }    save(stu, n);}int  FindByNum (STU stu[],int n ,char *str)       /*按学号查找*/{	int i;	for(i =0; i<n; i++)/*若找到,则返回对应下标*/		if(strcmp (stu[i].ID,str)==0)			return i;	return -1;}void output (STU stu[],int n)              /*输出所有信息*/{    int i;    /*打印表头*/        printf("%8s%8s%4s%8s%8s%8s%8s%8s%8s%8s\n","ID","NAME","SEX","SCORE1","SCORE2","SCORE3","SCORE4", "SCORE5","total","avg");    /*打印所有记录*/    for(i=0;i<n; i++)    	PrintRecord(&stu[i]);    system( "pause");}
void PrintRecord(STU *sPtr)                /*输出一条记录*/{    int i;        printf("%8s%8s%4c",sPtr->ID,sPtr->name, sPtr->sex);    for(i = 0; i<5; i++)    	printf("%8.2f",sPtr->score[i]);    	printf("%8.2f%8.2f",sPtr->total, sPtr->avg);    printf("\n");    }