某班有最多不超过30人（具体人数由键盘输入）参加期末考试，最多不超过6门（具体门数由键盘输入）。使

Question

某班有最多不超过30人（具体人数由键盘输入）参加期末考试，最多不超过6门（具体门数由键盘输入）。使用文件编程成实现如下菜单驱动的学生成绩管理系统。
1.从文件读入每个学生个人信息和成绩信息，可以由键盘输入文件名。读入成功提示读入学生记录的个数，不成功提示相应出错信息。

2.计算每门课程的总分和平均分；
3.计算每个学生的总分和平均分；

4.按每个学生的总分由高到低排出名次表；
5.按学号由小到大排出成绩表；

6.按姓名的字典顺序排出成绩表；
7.按学号查询学生排名及其考试成绩；

8.按姓名查询学生排名及其考试成绩；
9.按优秀（100-90）、良好（89-80）、中等（79-70）、及格（69-60）、不及格（59-0）5个类别，对每门课程分别统计每个类别的人数以及所占的百分比；并将计算结果输出到屏幕；

10.输出每个学生的学号、姓名、各科考试成绩、总分和平均分；
11.将每个学生的个人信息和成绩写入文件，可由键盘输入文件名；

要求程序运行后先显示如下菜单，并提示用户输入选项（菜单式循环显示，直到选择0.exit 整个程序退出）：

1.Read from a file
2.Calculate total and average score of every course

3.Calculate total and average score of every student
4.Sort in descending order by total score of every student

5.Sort in ascending order by number
6.Sort in dictionary order by name

7.Search by number
8.Search by name

9.Statistic analysis for every course
10.List record

11.Write to file
0 . Exit

Please input your choice:

C++编程

Answer 1

#include  <stdio.h>

#include  <stdlib.h>

#include  <string.h>

#define   MAX_LEN  10           /* 字符串最大长度 */

#define   STU_NUM 30         /* 最多的学生人数 */

int   Menu(void);

void  ReadScore(long num[], char name[][MAX_LEN], float score[], int n);

void  AverSumofScore(float score[], int n);

void  SortbyScore(long num[], char name[][MAX_LEN], float score[], int n,

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(long num[], char name[][MAX_LEN], float score[], int n);

void  SortbyName(long num[], char name[][MAX_LEN], float score[], int n);

void  SearchbyNum(long num[], char name[][MAX_LEN], float score[], int n);

void  SearchbyName(long num[], char name[][MAX_LEN], float score[], int n);

void  StatisticAnalysis(float score[], int n);

void  PrintScore(long num[], char name[][MAX_LEN], float score[], int n) ;

int main()

{

char  ch;

int   n = 0;

float score[STU_NUM];

long num[STU_NUM];

char name[STU_NUM][MAX_LEN];

printf("Input student number(n<30):\n");

scanf("%d", &n);

while (1)

{

ch = Menu();            /* 显示菜单，并读取用户输入 */

switch (ch)

{

case 1:

ReadScore(num, name, score, n);

break;

case 2:

AverSumofScore(score, n);

break;

case 3:

SortbyScore(num, name, score, n, Descending);

printf("Sort in descending order by score:\n");

PrintScore(num, name, score, n);

break;

case 4:

SortbyScore(num, name, score, n, Ascending);

printf("Sort in ascending order by score:\n");

PrintScore(num, name, score, n);

break;

case 5:

AsSortbyNum(num, name, score, n);

printf("Sort in ascending order by number:\n");

PrintScore(num, name, score, n);

break;

case 6:

SortbyName(num, name, score, n);

printf("Sort in dictionary order by name:\n");

PrintScore(num, name, score, n);

break;

case 7:

SearchbyNum(num, name, score, n);

break;

case 8:

SearchbyName(num, name, score, n);

break;

case 9:

StatisticAnalysis(score, n);

break;

case 10:

PrintScore(num, name, score, n);

break;

case 0:

printf("End of program!");

exit(0);

default:

printf("Input error!\n");

}

}

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.Caculate total and average score of course\n");

printf("3.Sort in descending order by score\n");

printf("4.Sort in ascending order by score\n");

printf("5.Sort in ascending order by number\n");

printf("6.Sort in dictionary order by name\n");

printf("7.Search by number\n");

printf("8.Search by name\n");

printf("9.Statistic analysis\n");

printf("10.List record\n");

printf("0.Exit\n");

printf("Please Input your choice:\n");

scanf("%d", &itemSelected);     /* 读入用户输入 */

return itemSelected;

}

/* 函数功能：输入n个学生的某门课成绩 */

void ReadScore(long num[], char name[][MAX_LEN], float score[], int n)

{

int i;

printf("Input student's ID, name and score:\n");

for (i = 0; i < n; i++)

{

scanf("%ld%s%f", &num[i], name[i], &score[i]);

}

}

/* 函数功能：计算全班总分和平均分 */

void AverSumofScore(float score[], int n)

{

int    i;

float  sum = 0;

for (i = 0; i < n; i++)

{

sum = sum + score[i];

}

printf("sum=%.0f,aver=%.2f\n", sum, n > 0 ? sum / n : 0);

}

/* 函数功能：按选择法将数组score的元素值排序 */

void SortbyScore(long num[], char name[][MAX_LEN], float score[], int n,

int (*compare)(float a, float b))

{

int i, j, k;

for (i = 0; i < n - 1; i++)

{

k = i;

for (j = i + 1; j < n; j++)

{

if ((*compare)(score[j], score[k])) k = j;

}

if (k != i)

{

SwapFloat(&score[k], &score[i]); /* 交换成绩 */

SwapLong(&num[k], &num[i]);       /* 交换学号 */

SwapChar(name[k], name[i]);       /* 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序，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序，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_LEN];

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(long num[], char name[][MAX_LEN], float score[], int n)

{

int     i, j, k;

for (i = 0; i < n - 1; i++)

{

k = i;

for (j = i + 1; j < n; j++)

{

if (num[j] < num[k])  k = j;

}

if (k != i)

{

SwapFloat(&score[k], &score[i]); /* 交换成绩 */

SwapLong(&num[k], &num[i]);       /* 交换学号 */

SwapChar(name[k], name[i]);       /* 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(long num[], char name[][MAX_LEN], float score[], int n)

{

int    i, j;

for (i = 0; i < n - 1; i++)

{

for (j = i + 1; j < n; j++)

{

if (strcmp(name[j], name[i]) < 0)

{

SwapFloat(&score[i], &score[j]); /* 交换成绩 */

SwapLong(&num[i], &num[j]);       /* 交换学号 */

SwapChar(name[i], name[j]);       /* 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(long num[], char name[][MAX_LEN], float score[], int n)

{

long number;

int   i;

printf("Input the number you want to search:\n");

scanf("%ld", &number);

for (i = 0; i < n; i++)

{

if (num[i] == number)

{

printf("%ld\t%s\t%.0f\n", num[i], name[i], score[i]);

return;

}

}

printf("Not found!\n");

}

/* 函数功能：按姓名的字典顺序排出成绩表 */

void SearchbyName(long num[], char name[][MAX_LEN], float score[], int n)

{

char x[MAX_LEN];

int  i;

printf("Input the name you want to search:\n");

scanf("%s", x);

for (i = 0; i < n; i++)

{

if (strcmp(name[i], x) == 0)

{

printf("%ld\t%s\t%.0f\n", num[i], name[i], score[i]);

return;

}

}

printf("Not 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(float score[], int n)

{

int  i, total, t[6] = {0, 0, 0, 0, 0, 0};

for (i = 0; i < n; i++)

{

if (score[i] >= 0 && score[i] < 60)t[0]++;

else if (score[i] < 70)            t[1]++;

else if (score[i] < 80)            t[2]++;

else if (score[i] < 90)            t[3]++;

else if (score[i] < 100)           t[4]++;

else if (score[i] == 100)        t[5]++;

}

for (total = 0, i = 0; i <= 5; i++)

{

total = total + t[i];

}

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(long num[], char name[][MAX_LEN], float score[], int n)

{

int i;

for (i = 0; i < n; i++)

{

printf("%ld\t%s\t%.0f\n", num[i], name[i], score[i]);

}

}