作业7

4
`#include <stdio.h>

include <ctype.h>

int main() {
FILE *fp;
char ch;
int lines = 0;
int characters = 0;

fp = fopen("data4.txt", "r");
if (fp == NULL) {
perror("Error opening file");
return 1;
}

while ((ch = fgetc(fp))!= EOF) {
if (ch == '\n') {
lines++;
}
if (!isspace(ch)) {
characters++;
}
}
// 处理文件末尾没有换行符的情况
if (characters > 0) {
lines++;
}

fclose(fp);

printf("data4.txt统计结果：\n");
printf("行数：%d\n", lines);
printf("字符数(不计空白符)：%d\n", characters);

return 0;
}`

5
`#include <stdio.h>

include <string.h>

define N 10

typedef struct {
long id; // 准考证号
char name[20]; // 姓名
float objective; // 客观题得分
float subjective; // 操作题得分
float sum; // 总分
char result[10]; // 考试结果
} STU;

// 函数声明
void read(STU st[], int n);
void write(STU st[], int n);
void output(STU st[], int n);
int process(STU st[], int n, STU st_pass[]);

int main() {
STU stu[N], stu_pass[N];
int cnt;
double pass_rate;

printf("从文件读入%d个考生信息...\n", N);
read(stu, N);

printf("\n对考生成绩进行统计...\n");
cnt = process(stu, N, stu_pass);

printf("\n通过考试的名单:\n");
output(stu, N); // 输出所有考生完整信息到屏幕
write(stu, N); // 输出考试通过的考生信息到文件

pass_rate = 1.0 * cnt / N;
printf("\n本次等级考试通过率: %.2f%%\n", pass_rate*100);

return 0;
}

// 把所有考生完整信息输出到屏幕上
// 准考证号，姓名，客观题得分，操作题得分，总分，结果
void output(STU st[], int n) {
int i;

printf("准考证号\t姓名\t客观题得分\t操作题得分\t总分\t\t结果\n");
for (i = 0; i < n; i++)
printf("%ld\t\t%s\t%.2f\t\t%.2f\t\t%.2f\t\t%s\n", st[i].id, st[i].name, st[i].objective, st[i].subjective, st[i].sum, st[i].result);
}

// 从文本文件examinee.txt读入考生信息:准考证号，姓名，客观题得分，操作题得分
void read(STU st[], int n) {
int i;
FILE *fin;

fin = fopen("examinee.txt", "r");
if (!fin) {
printf("fail to open file\n");
return;
}

while (!feof(fin)) {
for (i = 0; i < n; i++)
fscanf(fin, "%ld %s %f %f", &st[i].id, st[i].name, &st[i].objective, &st[i].subjective);
}

fclose(fin);
}

// 把通过考试的考生完整信息写入文件list_pass.txt
// 准考证号，姓名，客观题得分，操作题得分，总分，结果
void write(STU s[], int n) {
int i;
FILE *fout;
fout = fopen("list_pass.txt", "w");
if (!fout) {
printf("fail to open file\n");
return;
}
fprintf(fout, "准考证号\t姓名\t客观题得分\t操作题得分\t总分\t\t结果\n");
for (i = 0; i < n; i++) {
if (strcmp(s[i].result, "Pass") == 0) {
fprintf(fout, "%ld\t\t%s\t%.2f\t\t%.2f\t\t%.2f\t\t%s\n", s[i].id, s[i].name, s[i].objective, s[i].subjective, s[i].sum, s[i].result);
}
}
fclose(fout);
}

// 对考生信息进行处理：计算每位考生考试总分、结果；统计考试通过的人数
int process(STU st[], int n, STU st_pass[]) {
int i, cnt = 0;
for (i = 0; i < n; i++) {
st[i].sum = st[i].objective + st[i].subjective;
if (st[i].sum >= 60) {
strcpy(st[i].result, "通过");
st_pass[cnt] = st[i];
cnt++;
} else {
strcpy(st[i].result, "不通过");
}
}
return cnt;
}`

6
`#include <stdio.h>

include <stdlib.h>

include <time.h>

define STUDENT_NUM 80

define SELECT_NUM 5

typedef struct {
int id;
char name[20];
char class[20];
} Student;

int main() {
Student students[STUDENT_NUM];
int selected[SELECT_NUM];
int i, j, k;
char filename[50];
FILE *fp;

FILE *listFile = fopen("list.txt", "r");
if (listFile == NULL) {
printf("无法打开文件list.txt\n");
return 1;
}
for (i = 0; i < STUDENT_NUM; i++) {
fscanf(listFile, "%d %s %s", &students[i].id, students[i].name, students[i].class);
}
fclose(listFile);

srand((unsigned int)time(NULL));

for (i = 0; i < SELECT_NUM; i++) {
int index;
do {
index = rand() % STUDENT_NUM;
} while (students[index].id == -1);
selected[i] = index;
students[index].id = -1;
}

printf("随机抽点的学生信息：\n");
for (i = 0; i < SELECT_NUM; i++) {
int index = selected[i];
printf("学号：%d，姓名：%s，班级：%s\n", students[index].id, students[index].name, students[index].class);
}

printf("请输入文件名：");
scanf("%s", filename);
fp = fopen(filename, "w");
if (fp == NULL) {
printf("无法打开文件%s\n", filename);
return 1;
}
fprintf(fp, "随机抽点的学生信息：\n");
for (i = 0; i < SELECT_NUM; i++) {
int index = selected[i];
fprintf(fp, "学号：%d，姓名：%s，班级：%s\n", students[index].id, students[index].name, students[index].class);
}
fclose(fp);

return 0;
}`