实验七

4

#include <ctype.h>

int main() 
{
    FILE *file;
    int line_count = 0;
    int char_count = 0;
    int ch;
    int in_line = 0;

    file = fopen("data4.txt", "r");
    if (file == NULL) 
    {
        printf("文件未找到\n");
        return 1;
    }

    while ((ch = fgetc(file)) != EOF) 
    {
        if (!isspace(ch)) 
        {
            char_count++;
        }
        if (ch == '\n') {
            line_count++;
            in_line = 0;
        } else {
            in_line = 1;
        }
    }

    if (in_line) 
    {
        line_count++;
    }

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

    fclose(file);
    return 0;
}    

5

#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);
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);   
    write(stu, N);    

    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;

    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);
}

void write(STU s[], int n) 
{
    FILE *fout;
    int i;
    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结果\n");
    for (i = 0; i < n; i++)
    {
        if (s[i].sum >= 60) 
        { 
            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);
}

int process(STU st[], int n, STU st_pass[]) 
{
   int i, pass_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[pass_count] = st[i];
            pass_count++;
        } else 
        {
            strcpy(st[i].result,"不通过");
        }
    }
    return pass_count; 
}

6

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

#define MAX_STUDENTS 100
#define NAME_LENGTH 50
#define WINNERS 5

int main() 
{
    FILE *fp;
    char students[MAX_STUDENTS][NAME_LENGTH];
    char winners[WINNERS][NAME_LENGTH];
    int count = 0;
    int selected[WINNERS] = {0};
    char filename[100];
    int i, j, random_num;

    fp = fopen("list.txt", "r");
    if (fp == NULL) 
    {
        printf("无法打开文件！\n");
        return 1;
    }

    while (fgets(students[count], NAME_LENGTH, fp) != NULL && count < MAX_STUDENTS) 
    {
        students[count][strcspn(students[count], "\n")] = 0;
        count++;
    }
    fclose(fp);

    if (count == 0) 
    {
        printf("没有学生名单！\n");
        return 1;
    }
    
    srand(time(NULL));

    for (i = 0; i < WINNERS && count > 0; i++) 
    {
        do {
            random_num = rand() % count;
            for (j = 0; j < i; j++) 
            {
                if (selected[j] == random_num) 
                {
                    random_num = -1; 
                    break;
                }
            }
        } while (random_num == -1);

        selected[i] = random_num;
        strcpy(winners[i], students[random_num]);
    }

    printf("中奖名单：\n");
    for (i = 0; i < WINNERS && i < count; i++) 
    {
        printf("%s\n", winners[i]);
    }

    printf("请输入要写入的文件名：");
    scanf("%s", filename);

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

    for (i = 0; i < WINNERS && i < count; i++) 
    {
        fprintf(fp, "%s\n", winners[i]);
    }

    fclose(fp);
    printf("中奖名单已写入 %s\n", filename);

    return 0;
}