這裏有壹個用C寫的，百度的排版不太好，將就看吧。
稍微說壹下思路。先是定義壹個學生結構，接著是壹個類似管理者的結構，管理者中存儲學生數組，並記錄學生數。之後則是壹系列操作，包括排序、計算平均值、讀寫文件等等，這些操作基本上都以管理者作為操作對象。最後當然就是界面菜單的處理。
運行程序時必須有stud.txt文件，另外，保存文件的操作沒有設為自動進行，而是通過菜單選擇進行。默認保存的文件名有stud.txt和stud2.txt，如果要存為其他文件需要自己輸入文件名。
每個函數都有說明，希望妳能看明白。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define NAME_MAX_LENGTH 25
#define STUDENT_MAX_NUMBER 100
/* 定義學生信息結構 */
struct Student
{
int id;
char name[NAME_MAX_LENGTH];
int age;
float score;
};
/* 管理者結構 */
struct Manager
{
struct Student stus[STUDENT_MAX_NUMBER];
int size;
int stu_count;
};
/********************** 相關操作 ********************/
/*
交換兩個學生信息
*/
void SwapStudents(struct Student *pStu1, struct Student *pStu2)
{
struct Student temp;
temp.id = pStu1->id;
temp.age = pStu1->age;
temp.score = pStu1->score;
strcpy(temp.name, pStu1->name);
pStu1->id = pStu2->id;
pStu1->age = pStu2->age;
pStu1->score = pStu2->score;
strcpy(pStu1->name, pStu2->name);
pStu2->id = temp.id;
pStu2->age = temp.age;
pStu2->score = temp.score;
strcpy(pStu2->name, temp.name);
}
/*
初始化管理者
*/
void InitializeManager(struct Manager *pm)
{
int i;
pm->size = NAME_MAX_LENGTH;
pm->stu_count = 0;
for (i=0; i<pm->size; ++i)
{
pm->stus[i].id = 0;
pm->stus[i].name[0] = 0;
pm->stus[i].age = 0;
pm->stus[i].score = 0.0f;
}
}
/*
查找壹個學生
id: 學生id
return: 指定學生的索引，查找失敗返回-1
*/
int SearchForOne(struct Manager *pm, int id)
{
int i;
for (i=0; i<pm->stu_count; ++i)
{
if (pm->stus[i].id != id) continue;
return i;
}
return -1;
}
/*
從文件中加載學生信息
szFileName: 文件名
return: 學生數。若讀取失敗，則返回0。
P.S. 如果文件中的學生數超過數組大小，則多余部分不會讀入
*/
int LoadStudentsInfo(struct Manager *pm, char *szFileName)
{
char ch, str[10];
int i;
FILE *fp = fopen(szFileName, "r");
if (!fp) return 0;
for (i=0; i<pm->size; ++i)
{
if (fscanf(fp, "%d%c%s%d%s", &pm->stus[i].id, &ch, pm->stus[i].name,
&pm->stus[i].age, str) == EOF) break;
pm->stus[i].score = (float)atof(str);
}
fclose(fp);
return pm->stu_count = i;
}
/*
將學生信息保存到文件中
szFileName: 文件名
*/
int SaveStudentsInfo(struct Manager *pm, char *szFileName)
{
char ch = 'a';
int i;
FILE *fp = fopen(szFileName, "w");
if (!fp) return 0;
for (i=0; i<pm->stu_count; ++i)
{
fprintf(fp,"%03d%c %s %d %g\n", pm->stus[i].id, ch, pm->stus[i].name,
pm->stus[i].age, pm->stus[i].score);
}
fclose(fp);
return 1;
}
/*
根據ID排序
mode: 0 - 升序，非0 - 降序
*/
void SortByID(struct Manager *pm, int mode)
{
int i, j;
int flag = 1;
if (mode)
{
for (i=0; (i+1<pm->stu_count) && flag; ++i)
{
flag = 0;
for (j=0; j+i+1<pm->stu_count; ++j)
{
if (pm->stus[j].id < pm->stus[j+1].id)
{
SwapStudents(pm->stus+j, pm->stus+j+1);
flag = 1;
}
}
}
return;
}
for (i=0; (i+1<pm->stu_count) && flag; ++i)
{
flag = 0;
for (j=0; j+i+1<pm->stu_count; ++j)
{
if (pm->stus[j].id > pm->stus[j+1].id)
{
SwapStudents(pm->stus+j, pm->stus+j+1);
flag = 1;
}
}
}
}
/*
根據成績排序
mode: 0 - 升序，非0 - 降序
*/
void SortByScore(struct Manager *pm, int mode)
{
int i, j;
int flag = 1;
if (mode)
{
for (i=0; (i+1<pm->stu_count) && flag; ++i)
{
flag = 0;
for (j=0; j+i+1<pm->stu_count; ++j)
{
if (pm->stus[j].score < pm->stus[j+1].score)
{
SwapStudents(pm->stus+j, pm->stus+j+1);
flag = 1;
}
}
}
return;
}
for (i=0; (i+1<pm->stu_count) && flag; ++i)
{
flag = 0;
for (j=0; j+i+1<pm->stu_count; ++j)
{
if (pm->stus[j].score > pm->stus[j+1].score)
{
SwapStudents(pm->stus+j, pm->stus+j+1);
flag = 1;
}
}
}
}
/*
平均成績
*/
float AverageScore(struct Manager *pm)
{
float sum = 0.0f;
int i;
for (i=0; i<pm->stu_count; ++i) sum += pm->stus[i].score;
return sum / pm->stu_count;
}
/*
打印壹個學生的信息
index: 學生索引
return: 非法索引值將返回0
*/
int PrintOne(struct Manager *pm, int index)
{
char ch = 'a';
if (index<0 || index>=pm->size) return 0;
printf("* * * * * * * * * * * * * *\n");
printf("ID:\t%03d%c\nName:\t%s\nAge:\t%d\nScore:\t%.1f\n", pm->stus[index].id, ch,
pm->stus[index].name, pm->stus[index].age, pm->stus[index].score);
printf("* * * * * * * * * * * * * *\n");
return 1;
}
/*
打印所有學生信息
*/
void PrintAll(struct Manager *pm)
{
char ch = 'a';
int i;
printf("* * * * * * * * * * * * * * * *\n");
printf("ID Name\tAge\tScore\n");
for (i=0; i<pm->stu_count; ++i)
{
printf("%03d%c: %s\t%d\t%.1f\n", pm->stus[i].id, ch,
pm->stus[i].name, pm->stus[i].age, pm->stus[i].score);
}
printf("* * * * * * * * * * * * * * * *\n");
}
/*
清除緩沖區中的剩余字符
*/
void clear()
{
for (; getchar()!=10; );
}
/*
界面處理
rank: 菜單級次。1: 顯示所有學生信息；
2: 顯示指定學生信息；
3: 修改指定學生信息；
4: 平均成績；
5: 按ID升序排列；
6: 按成績降序排列；
7: 重新從文件中讀入學生數據；（文件可選）
8: 將當前學生信息保存到文件中；（文件可選）
9. 退出程序
return: 如果選擇退出，返回0；否則返回非0值
*/
int InteraceProc(int rank, struct Manager *pm)
{
char sel = 0;
char szFile[30];
int id, index, res;
int age;
float score;
switch (rank)
{
case 0:
printf("\n");
printf("- - - - - - - - - - - - - - - - -\n");
printf("1. Information of all students\n");
printf("2. Information of one student\n");
printf("3. Modify data of one student\n");
printf("4. Average score\n");
printf("5. Sort by ID\n");
printf("6. Sort by score\n");
printf("7. Reload data from...\n");
printf("8. Save current data as...\n");
printf("9. Exit\n");
printf("- - - - - - - - - - - - - - - - -\n");
printf("Please choose one: ");
break;
case 1:
printf("\n");
PrintAll(pm);
clear();
break;
case 2:
id = -1;
printf("\nSpecify the student by ID: ");
scanf("%d", &id);
clear();
index = SearchForOne(pm, id);
if (index < 0) printf("Can't find the student.\n");
else PrintOne(pm, index);
clear();
break;
case 3:
printf("\nSpecify the student by ID: ");
scanf("%d", &id);
clear();
index = SearchForOne(pm, id);
if (index < 0)
{
printf("Can't find the student.\n");
break;
}
PrintOne(pm, index);
printf("Input the new age and new score: ");
res = scanf("%d %f", &age, &score);
clear();
if (!res) break;
printf("Are you sure? (y/n) ");
res = scanf("%c", &sel);
clear();
if (sel!='y' && sel!='Y') break;
pm->stus[index].age = age;
pm->stus[index].score = score;
PrintOne(pm, index);
clear();
break;
case 4:
score = AverageScore(pm);
printf("\nThe average score: %.2f", score);
clear();
break;
case 5:
printf("Are you sure? (y/n) ");
res = scanf("%c", &sel);
clear();
if (sel!='y' && sel!='Y') break;
printf("\n");
SortByID(pm, 0);
PrintAll(pm);
clear();
break;
case 6:
printf("Are you sure? (y/n) ");
res = scanf("%c", &sel);
clear();
if (sel!='y' && sel!='Y') break;
printf("\n");
SortByScore(pm, 1);
PrintAll(pm);
clear();
break;
case 7:
case 8:
printf("\n1. stud.txt");
printf("\n2. stud2.txt");
printf("\n3. other file");
printf("\n4. return");
printf("\nchoose one: ");
res = scanf("%d", &index);
clear();
if (!res || index<1 || index>3) break;
switch (index)
{
case 1: strcpy(szFile, "stud.txt"); break;
case 2: strcpy(szFile, "stud2.txt"); break;
case 3:
printf("Input the file name: ");
scanf("%s", szFile);
clear();
break;
}
printf("Are you sure? (y/n) ");
res = scanf("%c", &sel);
clear();
if (sel!='y' && sel!='Y') break;
if (rank == 7) res = LoadStudentsInfo(pm, szFile);
else res = SaveStudentsInfo(pm, szFile);
if (!res) printf("Can't open the file!\n");
break;
case 9:
printf("\nThe program end.");
getchar();
return 0;
}
return 1;
}
/******************* 主函數 *******************/
int main()
{
int sel, res;
struct Manager manager;
/* 程序的正常運行需要確保存在stud.txt文件 */
InitializeManager(&manager);
if (!LoadStudentsInfo(&manager, "stud.txt"))
{
printf("Can't load students data.\n");
printf("The program abort.");
getchar();
return -1;
}
for (; ; )
{
InteraceProc(0, &manager);
res = scanf("%d", &sel);
clear(); /* 如果沒有這壹句，在主菜單中輸入非數字字符時，程序將陷入死循環 */
if (!res || !sel) continue;
if (!InteraceProc(sel, &manager)) break;
}
return 0;
}