实验7

task4

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
void count_lines_and_characters(const char *filename);
int main() {
    const char *filename = "data4.txt";
    count_lines_and_characters(filename);
    return 0;
}
void count_lines_and_characters(const char *filename) {
    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        printf("无法打开文件：%s\n", filename);
        return;
    }
    int line_count = 0;
    int char_count = 0;
    int ch;
    while ((ch = fgetc(file)) != EOF) {
        if (ch == '\n') {
            line_count++;
        } else if (!isspace(ch)) {
            char_count++;
        }
    }
    fclose(file);
    printf("%s统计结果：\n", filename);
    printf("行数：%d\n", line_count + 1);
    printf("字符数(不计空白符)：%d\n", char_count);
}

task5

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

#define N 10

typedef struct {
    long id;
    char name[20];
    float objective;
    float subjective;
    float sum;
    char result[10];
} STU;
void read(STU st[], int n);
void write(STU st[], int n);
int process(STU st[], int n, STU st_pass[]);
void output(STU st[], int n);
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);
    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;
}
void write(STU st[], int n) {
    FILE *fout = fopen("list_pass.txt", "w");
    if (!fout) {
        printf("fail to open file\n");
        return;
    }
    for (int 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);
}
int process(STU st[], int n, STU st_pass[]) {
    int cnt = 0;
    for (int 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");
            cnt++;
            memcpy(&st_pass[i - cnt + 1], &st[i], sizeof(STU));
        } else {
            strcpy(st[i].result, "未通过");
        }
    }
    return cnt;
}
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结果\n");
    for (i = 0; i < n; i++)
        printf("%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);
}
void read(STU st[], int n) {
    int i;
    FILE *fin;
    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);
}

 task6

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

#define N 100
#define M 5

int main() {
    char s[N][N];
    FILE *fp;
    int i, n;
    int flag[N] = {0};
    fp = fopen("list.txt", "r");
    if (!fp) {
        perror("list.txt");
        return 1;
    }
    i = 0;
    while (fgets(s[i], N, fp) != NULL) {
        n = i;
        i++;
    }
    fclose(fp);
    srand((unsigned int)time(NULL));
    printf("------中奖名单------\n");
    for (int k = 0; k < M; k++) {
        int r;
        do {
            r = rand() % (n + 1);
        } while (flag[r]);
        flag[r] = 1;
        printf("%s", s[r]);
    }
    printf("\n");

    fp = fopen("20251222.txt", "w");
    if (!fp) {
        perror("20251222.txt");
        return 1;
    }
    for (int k = 0; k < M; k++) {
        int r;
        do {
            r = rand() % (n + 1);
        } while (flag[r]);
        flag[r] = 1;
        fprintf(fp, "%s\n", s[r]);
    }
    fclose(fp);
    printf("文件保存成功！\n");

    printf("------20251222中奖名单------\n");
    char temp[N];
    for (int k = 0; k < M; k++) {
        for (int j = k + 1; j < M; j++) {
            if (strncmp(s[k], s[j], 9) > 0) {
                strcpy(temp, s[k]);
                strcpy(s[k], s[j]);
                strcpy(s[j], temp);
            }
        }
    }
    for (int k = 0; k < M; k++) {
        printf("%s", s[k]);
    }
    printf("\n");

    fp = fopen("20251222.txt", "a");
    if (!fp) {
        perror("20251222.txt");
        return 1;
    }
    for (int k = 0; k < M; k++) {
        fprintf(fp, "%s\n", s[k]);
    }
    fclose(fp);
    printf("文件保存成功！\n");

    return 0;
}