实验七

任务四

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#include <stdio.h>
int main() {
    FILE* f = fopen("C:\\Users\\Lenovo\\Desktop\\实验七\\data4.txt.txt", "r");
    int lines = 0, chars = 0, c;

    while ((c = fgetc(f)) != EOF) {
        if (c == '\n') lines++;           
        if (c != ' ' && c != '\n' && c != '\t' && c != '\r')
            chars++;                     
    }

    fclose(f);
    printf("data4.txt统计结果：\n");
    printf("行数：    %d\n", lines + 1);  
    printf("字符数(不计空白符)：    %d\n", chars);
    return 0;
}

任务五

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#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <string.h>
#include <errno.h>
#define N 10

typedef struct {
    long id;             // 准考证号
    char name[20];       // 姓名
    float objective;     // 客观题得分（40分制）
    float subjective;    // 操作题得分（60分制）
    float sum;           // 总分
    char result[10];     // 考试结果（通过/未通过）
} 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所有考生完整信息:\n");
    output(stu, N);   // 输出所有考生完整信息到屏幕
    write(stu_pass, cnt);    // 写入通过考生信息到文件
    pass_rate = 1.0 * cnt / N;
    printf("\n本次等级考试通过率: %.2f%%\n", pass_rate * 100);
    return 0;
}

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);
}

void read(STU st[], int n) {
    int i;
    FILE* fin;
    errno_t err = fopen_s(&fin, "C:\\Users\\Lenovo\\Desktop\\实验七\\examinee.txt.txt", "r");
    if (err != 0 || fin == NULL) {
        printf("fail to open file examinee.txt\n");
        return;
    }
    for (i = 0; i < n; i++) {
        int ret = fscanf_s(fin, "%ld %s %f %f", &st[i].id, st[i].name, (unsigned)(sizeof(st[i].name) / sizeof(st[i].name[0])), &st[i].objective, &st[i].subjective);
        if (ret != 4) {
            printf("第%d个考生信息读取失败\n", i + 1);
            break;
        }
    }
    fclose(fin);
}

void write(STU s[], int n) {
    int i;
    FILE* fout;
    errno_t err = fopen_s(&fout, "C:\\Users\\Lenovo\\Desktop\\实验七\\examinee.txt.txt", "w");
    if (err != 0 || fout == NULL) {
        printf("fail to open file list_pass.txt\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结果\n");
    for (i = 0; i < n; i++) {
        fprintf(fout, "%ld\t%s\t%.2f\t%.2f\t%.2f\t%s\n",
            s[i].id, s[i].name, s[i].objective,
            s[i].subjective, s[i].sum, s[i].result);
    }
    fclose(fout);
    printf("\n通过考生信息已保存到list_pass.txt\n");
}

int process(STU st[], int n, STU st_pass[]) {
    int pass_count = 0;
    size_t result_len = sizeof(st[0].result) / sizeof(st[0].result[0]);
    for (int i = 0; i < n; i++) {
        st[i].sum = st[i].objective + st[i].subjective;
        if (st[i].sum >= 60.0) {
            strncpy_s(st[i].result, result_len, "通过", _TRUNCATE);
            st_pass[pass_count] = st[i];
            pass_count++;
        }
        else {
            strncpy_s(st[i].result, result_len, "未通过", _TRUNCATE);
        }
    }
    return pass_count;
}

任务六

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#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define N 80  
#define WINNERS 5  
#define MAX_FILENAME 100
#define MAX_ID_LEN 20
#define MAX_NAME_LEN 20

typedef struct {
    char id[MAX_ID_LEN];
    char name[MAX_NAME_LEN];
} Student;

int readStudents(Student students[], const char* filename);
void randomSelect(Student students[], int total, Student winners[], int count);
void displayWinners(Student winners[], int count);
void writeToFile(Student winners[], int count, const char* filename);
void sortByID(Student winners[], int count);

int main() {
    Student students[N];
    Student winners[WINNERS];
    char filename[MAX_FILENAME];
    int count;

    srand(time(NULL));

    count = readStudents(students, "C:\\Users\\Lenovo\\Desktop\\实验七\\list.txt");
    if (count == 0) {
        printf("错误：未能读取到学生信息\n");
        return 1;
    }

    if (count < WINNERS) {
        printf("错误：学生数量不足%d人（当前只有%d人）\n", WINNERS, count);
        return 1;
    }

    randomSelect(students, count, winners, WINNERS);
    sortByID(winners, WINNERS);

    printf("\n=== 中奖名单 ===\n");
    displayWinners(winners, WINNERS);

    printf("\n请输入要保存的文件名：");
    fgets(filename, MAX_FILENAME, stdin);

    filename[strcspn(filename, "\n")] = '\0';

    if (strlen(filename) == 0) {
        strcpy_s(filename, MAX_FILENAME, "中奖名单.txt");
    }

    writeToFile(winners, WINNERS, filename);
    printf("\n中奖名单已保存到文件：%s\n", filename);

    return 0;
}

int readStudents(Student students[], const char* filename) {
    FILE* file;
    int i = 0;

    if (fopen_s(&file, filename, "r") != 0 || file == NULL) {
        printf("无法打开文件：%s\n", filename);
        return 0;
    }

    printf("正在读取文件：%s\n", filename);

    while (i < N && fscanf_s(file, "%19s %19s",
        students[i].id, (unsigned)_countof(students[i].id),
        students[i].name, (unsigned)_countof(students[i].name)) == 2) {
        i++;
    }

    fclose(file);
    printf("成功读取 %d 名学生信息\n", i);
    return i;
}

void randomSelect(Student students[], int total, Student winners[], int count) {
    int* flag = (int*)calloc(total, sizeof(int));  

    int selected = 0;
    int random_index;

    if (flag == NULL) {
        printf("内存分配失败！\n");
        exit(1);
    }

    printf("\n开始随机抽奖...\n");
    printf("总参与人数：%d人，将抽取%d名幸运者\n", total, count);

    while (selected < count) {
        random_index = rand() % total;

        if (flag[random_index] == 0) {
            winners[selected] = students[random_index];
            flag[random_index] = 1;
            selected++;

            printf("第%d位中奖者：%s %s\n", selected,
                winners[selected - 1].id, winners[selected - 1].name);
        }
    }

    free(flag);  
}

void displayWinners(Student winners[], int count) {
    printf("序号\t学号\t\t姓名\n");
    printf("--------------------------------\n");

    for (int i = 0; i < count; i++) {
        printf("%d\t%s\t\t%s\n", i + 1, winners[i].id, winners[i].name);
    }
}

void writeToFile(Student winners[], int count, const char* filename) {
    FILE* file;

    if (fopen_s(&file, filename, "w") != 0 || file == NULL) {
        printf("无法创建文件：%s\n", filename);
        return;
    }

    fprintf(file, "=== 中奖名单 ===\n");
    fprintf(file, "抽取时间：%s", ctime(&(time_t) { time(NULL) }));
    fprintf(file, "序号\t学号\t\t姓名\n");
    fprintf(file, "--------------------------------\n");

    for (int i = 0; i < count; i++) {
        fprintf(file, "%d\t%s\t\t%s\n", i + 1, winners[i].id, winners[i].name);
    }

    fclose(file);
}

void sortByID(Student winners[], int count) {
    Student temp;

    for (int i = 0; i < count - 1; i++) {
        for (int j = 0; j < count - 1 - i; j++) {
            if (strcmp(winners[j].id, winners[j + 1].id) > 0) {
                temp = winners[j];
                winners[j] = winners[j + 1];
                winners[j + 1] = temp;
            }
        }
    }
}