实验七

任务4

#include <stdio.h>
int main() {
    FILE *fp;
    char ch;
    int lines = 0, chars = 0;
    fp = fopen("C:\\Users\\admin\\Desktop\\data4.txt", "r");
    if (fp == NULL) {
        printf("fail to open file to read\n");
        return 1;
    }
    while ((ch = fgetc(fp)) != EOF) {
        if (ch == '\n') {
            lines++; 
        } else if (ch != ' ' && ch != '\t' && ch != '\n') {
            chars++;
        }
    }
    lines++;
    fclose(fp);
    printf("data4.txt统计结果：\n");
    printf("行数：%d\n", lines);
    printf("字符数（不统计空白符）：%d\n", chars);
    return 0;
}

任务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: 已完成\n", N);
    read(stu, N);

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

    printf("\n所有考生完整信息:\n");
    output(stu, N);   

    printf("\n通过考试的名单写入文件: 已完成!\n");
    write(stu_pass, cnt);

    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("C:\\Users\\admin\\Desktop\\examinee.txt", "r");
    if (!fin) {
        printf("fail to open file\n");
        return;
    }

    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);
}

// 对考生信息进行处理：计算每位考生考试总分、结果；统计并返回通过考试的人数
int process(STU st[], int n, STU st_pass[]) {
    // 待补足
    // xxx
    int i, count = 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[count] = st[i];
            count++;
        } else {
            strcpy(st[i].result, "不通过");
        }
    } 
    return count;
}

// 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 st[], int n) {
    // 待补足
    // xxx
    int i;
    FILE *fout;
    
    fout = fopen("list_pass.txt", "w");
    if (!fout) {
        printf("fail to open file to writing\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", 
                st[i].id, st[i].name, st[i].objective, 
                st[i].subjective, st[i].sum, st[i].result);
    }
    
    fclose(fout);
}

任务6

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

#define MAX_STUDENTS 80
#define WINNERS 5
#define MAX_LINE 256

typedef struct {
    char id[20];
    char name[50];
    char classs[50];
} Student;

int main() {
    FILE *fp;
    Student students[MAX_STUDENTS];
    int count = 0;
    int i, j;
    int winner_indices[WINNERS];
    int duplicate;
    char filename[100];
    fp = fopen("C:\\Users\\admin\\Desktop\\list.txt", "r");
    if (fp == NULL) {
        printf("错误：无法打开文件 list.txt\n");
        return 1;
    }
    while (fscanf(fp, "%s %s %[^\n]", 
                  students[count].id, 
                  students[count].name, 
                  students[count].classs) == 3) {
        count++;
        if (count >= MAX_STUDENTS) break;
    }
    fclose(fp);

    if (count < WINNERS) {
        printf("错误：学生人数不足 %d 人\n", WINNERS);
        return 1;
    }
    srand((unsigned)time(NULL));

    for (i = 0; i < WINNERS; i++) {
        do {
            winner_indices[i] = rand() % count;
            duplicate = 0;
            for (j = 0; j < i; j++) {
                if (winner_indices[j] == winner_indices[i]) {
                    duplicate = 1;
                    break;
                }
            }
        } while (duplicate);
    }
    printf("\n---中奖名单---\n");
    for (i = 0; i < WINNERS; i++) {
        int idx = winner_indices[i];
        printf("%-12s%-12s%s\n", 
               students[idx].id, 
               students[idx].name, 
               students[idx].classs);
    }
    printf("\n---保存到文件---\n");
    printf("输入文件名：");
    scanf("%s", filename);

    fp = fopen(filename, "w");
    if (fp == NULL) {
        printf("错误：无法创建文件 %s\n", filename);
        return 1;
    }

    fprintf(fp, "---中奖名单---\n");
    for (i = 0; i < WINNERS; i++) {
        int idx = winner_indices[i];
        fprintf(fp, "%-12s%-12s%s\n", 
                students[idx].id, 
                students[idx].name, 
                students[idx].classs);
    }
    fclose(fp);

    printf("保存成功！\n");
    system("pause");
    return 0;
}