实验7

task4

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

int main() {
FILE *fp;
int line_cnt = 0;
int char_cnt = 0;
int ch;
int last_ch = '\n';
int has_content = 0;

fp = fopen("data4.txt", "r");

while ((ch = fgetc(fp)) != EOF) {
    has_content = 1;
    last_ch = ch;

    if (ch == '\n')
        line_cnt++;

    if (ch != ' ' && ch != '\n' && ch != '\t')
        char_cnt++;
    }

if (has_content && last_ch != '\n')
    line_cnt++;

fclose(fp);

printf("data4.txt统计结果:\n");
printf("行数:\t\t\t%d\n", line_cnt);
printf("字符数(不计空白符):\t%d\n", char_cnt);
system("pause");
return 0;
}

 

task5

#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
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
void read(STU st[], int n) {
    int i;
    FILE *fin = fopen("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：计算总分、结果，返回通过人数
int process(STU st[], int n, STU st_pass[]) {
    int cnt = 0;
    int i;
    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];
        } else {
            strcpy(st[i].result, "未通过");
        }
    }
    return cnt;
}

// 将通过考试的考生信息写入文件list_pass.txt
void write(STU st[], int n) {
    FILE *fout = fopen("list_pass.txt", "w");
    if (!fout) {
        printf("无法创建文件 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\t结果\n");
    int i;
    for (i = 0; i < n; i++) {
        fprintf(fout, "%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);
    }
    fclose(fout);
}

 

task6

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

#define MAX_STUDENTS 100

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

int main() {
    FILE *fp;
    Student students[MAX_STUDENTS];
    int count = 0;
    char filename[100];
    int i, j, chosen[5], rand_idx;

    // 1. 打开并读取 list.txt
    fp = fopen("list.txt", "r");
    if (fp == NULL) {
        printf("无法打开文件 list.txt\n");
        return 1;
    }
    while (fscanf(fp, "%s %s %s", students[count].id, students[count].name, students[count].class_name) == 3) {
        count++;
        if (count >= MAX_STUDENTS) break;
    }
    fclose(fp);

    if (count < 5) {
        printf("学生人数不足5人，无法抽奖\n");
        return 1;
    }

    // 2. 随机抽取5个不重复的索引
    srand((unsigned)time(NULL));
    for (i = 0; i < 5; i++) {
        do {
            rand_idx = rand() % count;
            // 检查是否已经选过
            int duplicate = 0;
            for (j = 0; j < i; j++) {
                if (chosen[j] == rand_idx) {
                    duplicate = 1;
                    break;
                }
            }
            if (!duplicate) {
                chosen[i] = rand_idx;
                break;
            }
        } while (1);
    }

    // 3. 输出到屏幕
    printf("---中奖名单---\n");
    for (i = 0; i < 5; i++) {
        printf("%s\t%s\t%s\n", students[chosen[i]].id, students[chosen[i]].name, students[chosen[i]].class_name);
    }

    // 4. 输入文件名并保存到文件
    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("无法创建文件 %s\n", filename);
        return 1;
    }
    fprintf(fp, "---中奖名单---\n");
    for (i = 0; i < 5; i++) {
        fprintf(fp, "%s\t%s\t%s\n", students[chosen[i]].id, students[chosen[i]].name, students[chosen[i]].class_name);
    }
    fclose(fp);
    printf("保存成功！\n");

    return 0;
}