学生成绩管理系统（C语言版）

#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#define MAX_LRN  10
#define STU_NUM 30
#define COURSE_NUM 6
typedef struct student
{
    long num;
    char name[MAX_LRN];
    float score[COURSE_NUM];
    float sum;
    float aver;
}STU;
int Menu(void);
void ReadScore(STU stu[],int n,int m);
void AverSumofEveryStudent(STU stu[],int n ,int m);
void AverSumofEveryCourse(STU stu[],int n ,int m);
void SortbyScore(STU stu[],int n ,int m,int(*compare)(float a,float b));
int Ascending(float a,float b);
int Descending(float a,float b);
void SwapFloat(float *x,float *y);
void SwapLong (long*x,long*y);
void SwapChar(char x[],char y[]);
void AsSortbyNum(STU stu[],int n,int m);
void SortbyName(STU stu[],int n,int m);
void SearchbyNum(STU stu[],int n,int m);
void SearchbyName(STU stu[],int n,int m);
void StatisticAnalysis(STU stu[],int n,int m);
void PrintScore(STU stu[],int n,int m);
void WritetoFile(STU record[],int n,int m);
void ReadfromFile(STU record[],int *n,int *m);
int main(void)
{
    char  ch;
    int  n = 0,m = 0;
    STU stu[STU_NUM];
    printf("Input student number(n<%d):",STU_NUM);
    scanf("%d",&n);
    printf("Input course number(m<=%d):",COURSE_NUM);
    scanf("%d",&m);
    while(1)
    {
        ch = Menu();
        switch(ch)
        {
            case 1:ReadScore(stu, n ,m);
            break;
            case 2:AverSumofEveryCourse(stu,n,m);
            break;
            case 3:AverSumofEveryStudent(stu,n,m);
            break;
            case 4:SortbyScore(stu,n,m,Descending);
            printf("\nSort in descending order by score:\n");
            PrintScore(stu,n,m);
            break;
            case 5:SortbyScore(stu,n,m,Ascending);
            printf("\nSort in ascending order by score:\n");
            PrintScore(stu,n,m);
            break;
            case 6:AsSortbyNum(stu,n,m);
            printf("\nSort in ascending order by number:\n");
            PrintScore(stu,n,m);
            break;
            case 7:SortbyName(stu,n,m);
            printf("\nSort in dictionary order by name:\n");
            PrintScore(stu,n,m);
            break;
            case 8:SearchbyNum (stu,n,m);
            break;
            case 9:SearchbyName(stu,n,m);
            break;
            case 10:StatisticAnalysis(stu,n,m);
            break;
            case 11:PrintScore(stu,n,m);
            break;
            case 12:WritetoFile(stu,n,m);
            break;
            case 13:ReadfromFile(stu,&n,&m);
            break;
            case 0:printf("End of program!");
            exit (0);
            default:printf("Input error!");
        }
    }
    return 0;
}
 //函数功能：显示菜单并获得用户键盘输入的选项
 int Menu(void)
 {
     int itemSelected;
     printf("Management for Students'scores\n");
     printf("1.Input record\n");
     printf("2.Calculate total and average score of every course\n");
     printf("3.Calculate total and average score of every student\n");
     printf("4.Sort in descending order by score\n");
     printf("5.Sort in ascending order by score\n");
     printf("6.Sort in ascending order by number\n");
     printf("7.Sort in dictionary order by name\n");
     printf("8.Search by number\n");
     printf("9.Search by name\n");
     printf("10.Statistic analysis\n");
     printf("11.List record\n");
     printf("12.Write to a file\n");
     printf("13.Read from a file\n");
     printf("0.Exit\n");
     printf("Please Input your choice:");
     scanf("%d",&itemSelected);           //读入用户输入
     return itemSelected;
 }
 //函数功能：输入n个学生m门课成绩
 void ReadScore (STU stu[],int n,int m)
 {
     int i,j;
     printf("Input student's ID,name and score:\n");
     for(i=0;i<n;i++)
     {
         scanf("%ld%s",&stu[i].num,stu[i].name);
         for(j=0;j<m;j++)
         {
             scanf("%f",&stu[i].score[j]);
         }
     }
 }
 //函数功能：计算每个学生各门课程的总分和平均分
 void AverSumofEveryStudent(STU stu[],int n ,int m)
 {
     int i,j;
     for(i=0;i<n;i++)
     {
         stu[i].sum = 0 ;
         for(j=0;j<m;j++)
         {
             stu[i].sum = stu[i].sum+stu[i].score[j];
         }
         stu[i].aver=m>0?stu[i].sum/m : -1;
         printf("student %d:sum = %.0f,aver = %.0f\n",
               i+1,stu[i].sum,stu[i].aver );
     }
 }
 //函数功能：计算每门课程的总分和平均分
 void AverSumofEveryCourse(STU stu[],int n,int m)
 {
    int i,j;
    float sum[COURSE_NUM],aver[COURSE_NUM];
    for(j=0;j<m;j++)
    {
        sum[j]=0;
        for (i=0;i<n;i++)
        {
            sum[j]=sum[j]+stu[i].score[j];
        }
        aver[j] =n>0? sum[j]/n:-1;
        printf("course %d:sum=%.0f,aver=%.0f\n",j+1,sum[j],aver[j]);
    }
 }
 //函数功能：按选择法将数组sum的元素值排序
 void SortbyScore(STU stu[],int n ,int m,int(* compare)(float a,float b))
 {
     int i,j,k,t;
     for(i=0;i<n-1;i++)
     {
         k=i;
         for (j=i+1;j<n;j++)
         {
             if((* compare)(stu[j].sum,stu[k].sum))k=j;
         }
         if(k!=i)
         {
            for (t=0;t<m;t++)       //交换m门课程的成绩
            {
                SwapFloat(&stu[k].score[t],&stu[i].score[t]);
            }
             SwapFloat(&stu[k].sum,&stu[i].sum);  //交换总分
             SwapFloat(&stu[k].aver,&stu[i].aver);  //交换平均分
             SwapLong(&stu[k].num,&stu[i].num);   //交换学号
             SwapChar(stu[k].name,stu[i].name);  //交换姓名
         }
     }
 }
 //使数据按升序排序
 int Ascending(float a,float b)
 {
     return a<b;    //这样比较决定了按升序排列，如果a<b，则交换
 }
 //使数据按降序排序
 int Descending(float a,float b)
 {
     return a>b;    //这样比较决定了按降序排列，如果a>b，则交换
 }
 //交换两个单精度浮点型数据
 void SwapFloat(float *x,float *y)
 {
     float temp;
     temp = *x;
     *x = *y;
     *y =temp;
 }
 //交换两个长整型数据
 void SwapLong(long *x, long *y)
 {
     long temp;
     temp = *x;
     *x = *y;
     *y=temp;
 }
 //交换两个字符串
 void SwapChar(char x[],char y[])
 {
     char temp[MAX_LRN];
     strcpy(temp,x);
     strcpy(x,y);
     strcpy(y,temp);
 }
 //函数功能：按选择法将数组NUM的元素值按从低到高排序
 void AsSortbyNum(STU stu[],int n,int m)
 {
     int i,j,k,t;
     for(i=0;i<n-1;i++)
     {
         k=i;
         for (j=i+1;j<n;j++)
         {
             if(stu[j].num<stu[k].num)   k=j;
         }
         if(k!=i)
         {
             for(t=0;t<m;t++)    //交换m门课程的成绩
             {
                 SwapFloat(&stu[k].score[t],&stu[i].score[t]);
             }
             SwapFloat(&stu[k].sum,&stu[i].sum);   //交换总分
             SwapFloat(&stu[k].aver,&stu[i].aver);   //交换平均分
             SwapLong(&stu[k].num,&stu[i].num);   //交换学号
             SwapChar(stu[k].name,stu[i].name);  //交换姓名
         }
     }
 }
 //函数功能：交换法实现字符串按字典顺序排序
 void SortbyName(STU stu[],int n,int m)
 {
     int i,j,t;
     for (i=0;i<n-1;i++)
     {
         for(j=i+1;j<n;j++)
         {
         if(strcmp (stu[j].name,stu[i].name)<0)
         {
             for (t=0;t<m;t++)      //交换m门课程的成绩
             {
                 SwapFloat(&stu[i].score[t],&stu[j].score[t]);
             }
             SwapFloat(&stu[i].sum,&stu[j].sum);   //交换总分
             SwapFloat(&stu[i].aver,&stu[j].aver);   //交换平均分
             SwapLong(&stu[i].num,&stu[j].num);   //交换学号
             SwapChar(stu[i].name,stu[j].name);  //交换姓名
         }
       }
     }
 }
 //函数功能：按学号查找学生成绩并显示查找结果
 void SearchbyNum(STU stu[],int n,int m)
 {
     long number;
     int i,j;
     printf("Input the number you want to search:");
     scanf("%ld",&number);
     for(i=0;i<n;i++)
     {
         if(stu[i].num == number)
         {
             printf("%ld\t%s\t",stu[i].num,stu[i].name);
             for (j=0;j<m;j++)
             {
                 printf("%.0f\t",stu[i].score[j]);
             }
             printf("%.0f\t%.0f\n",stu[i].sum,stu[i].aver);
             return;
         }
     }
     printf("\nNot founf!\n");
 }
 //函数功能：按姓名的字典顺序排出成绩表
 void SearchbyName(STU stu[],int n,int m)
 {
     char x[MAX_LRN];
     int i,j;
     printf("Input the name you want to search:");
     scanf("%s",x);
     for (i=0;i<n;i++)
     {
         if(strcmp(stu[i].name,x) == 0)
         {
             printf("%ld\t%s\t",stu[i].num,stu[i].name);
             for(j=0;j<m;j++)
             {
                 printf("%.0f\t",stu[i].score[j]);
             }
             printf("%.0f\t%.0f\n",stu[i].sum,stu[i].aver);
             return;
         }
     }
     printf("\nNot found!\n");
 }
 //函数功能：统计各分数段的学生人数及所占的百分比
 void StatisticAnalysis(STU stu[],int n,int m)
 {
     int i,j,t[6];
     for(j=0;j<m;j++)
     {
         printf("For course %d:\n",j+1);
         memset(t,0,sizeof(t));
         for(i=0;i<n;i++)
         {
             if (stu[i].score[j]>=0 && stu[i].score[j]<60) t[0]++;
             else if(stu[i].score[j]<70)      t[1]++;
             else if(stu[i].score[j]<80)      t[2]++;
             else if(stu[i].score[j]<90)      t[3]++;
             else if(stu[i].score[j]<100)     t[4]++;
             else if(stu[i].score[j]==100)    t[5]++;
         }
         for(i=0;i<=5;i++)
         {
             if(i==0)printf("<60\t%d\t%.2f%% \n",t[i],(float)t[i]/n*100);
             else if(i==5)printf("%d\t%d\t%.2f%%  \n",
                (i+5)*10,t[i],(float)t[i]/n*100);
             else printf("%d-%d\t%d\t%.2f%%\n",(i+5)*10,(i+5)*10+9,
                t[i],(float)t[i]/n*100);
         }
     }
 }
 //函数功能：打印学生成绩
 void PrintScore(STU stu[],int n,int m )
 {
     int i,j;
     for(i=0;i<n;i++)
     {
         printf("%ld\t%s\t",stu[i].num,stu[i].name);
         for (j=0;j<m;j++)
         {
             printf("%.0f\t",stu[i].score[j]);
         }
         printf("%.0f\t%0f\n",stu[i].sum,stu[i].aver);
     }
 }
 //输入n个学生的学号、姓名及m门课程的成绩到文件 student。txt中
 void WritetoFile(STU stu[],int n,int m)
 {
     FILE *fp;
     int i,j;
     if((fp=fopen("student.txt","w")) ==NULL)
     {
         printf("Failure to open score.txt!\n");
         exit(0);
     }
     fprintf(fp,"%d\t%d\n",n,m);
     for (i=0;i<n;i++)
     {
      fprintf(fp,"%10ld%10s",stu[i].num,stu[i].name);
      for (j=0;j<m;j++)
      {
          fprintf(fp,"%10.0f",stu[i].score[j]);
      }
      fprintf(fp,"%10.0f%10.0f\n",stu[i].sum,stu[i].aver);
     }
     fclose(fp);
 }
 //从文件中读取学生的学号、姓名及成绩等信息写入到结构体数组stu中
 void ReadfromFile(STU stu[],int *n,int *m)
 {
     FILE *fp;
     int i,j;
     if((fp = fopen("student.txt","r")) == NULL)
     {
         printf("Failure to open score.txt!\n");
         exit(0);
     }
     fscanf(fp,"%d\t%d",n,m);       //从文件中读出学生人数和课程门数
     for (i=0;i<*n;i++)            //学生人数保存在n指向的存储单元
     {
         fscanf(fp,"%10ld",&stu[i].num);
         fscanf(fp,"%10s",stu[i].name);
         for (j=0;j<*m;j++)        //课程门数保存在m指向的存储单元
         {
             fscanf(fp,"%10f",&stu[i].score[j]);
         }
             fscanf(fp,"%10f%10f",&stu[i].sum,&stu[i].aver);
     }
     fclose(fp);
 }