experiment7

task1.1c

SHOW CODE

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

int main() {
    FILE *fp;
    char ch;
    int lines = 0;
    int chars = 0;
    fp = fopen("data4.txt", "r");
    if (fp == NULL) {
        printf("无法打开文件 data4.txt，请检查文件是否存在。\n");
        return 1;
    }
    while ((ch = fgetc(fp)) != EOF) {
        if (ch == '\n') {
            lines++;
        }
        if (!isspace(ch)) {
            chars++;
        }
    }

    if (chars > 0) {
        lines++; 
    }
    printf("data4.txt统计结果：\n");
    printf("行数：\t\t\t%d\n", lines);
    printf("字符数(不计空白符)：\t%d\n", chars);

    fclose(fp);
    
    return 0;
}

//预览效果如图所示

task2.1c

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#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...\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);   // 输出所有考生完整信息到屏幕
    write(stu, N);    // 输出考试通过的考生信息到文件

    pass_rate = 1.0 * cnt / N;
    printf("\n本次等级考试通过率: %.2f%%\n", pass_rate*100);

    return 0;
}

// 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，总分得分
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("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);
}


void write(STU s[], int n) {
    int i;
    FILE *fout;
    fout = fopen("list_pass.txt", "w");
    if (!fout) {
        printf("fail to open list_pass.txt\n");
        return;
    }
    fprintf(fout, "准考证号\t姓名\t客观题\t操作题\t总分\t结果\n");
    for (i = 0; i < n; i++) {
        fprintf(fout, "%ld\t\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;
    int 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, "未通过");
        }
    }
    return count; 
}

//预览效果如图所示

task3.1c

SHOW CODE

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

#define MAX_STUDENTS 100  
#define MAX_LEN 100       

int main() {
    char students[MAX_STUDENTS][MAX_LEN]; 
    int count = 0;
    FILE *fp_in, *fp_out;
    char out_filename[50];

 
    fp_in = fopen("list.txt", "r");
    if (fp_in == NULL) {
        printf("无法打开源文件 list.txt，请检查文件是否存在。\n");
        return 1;
    }

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

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

 
    srand((unsigned int)time(NULL));


    int lucky_indices[5];
    int picked_count = 0;
    while (picked_count < 5) {
        int r = rand() % count; 
      
        int is_repeated = 0;
        for (int i = 0; i < picked_count; i++) {
            if (lucky_indices[i] == r) {
                is_repeated = 1;
                break;
            }
        }

        if (!is_repeated) {
            lucky_indices[picked_count] = r;
            picked_count++;
        }
    }

    
    printf("请输入要保存的文件名（如 20251222.txt）: ");
    scanf("%s", out_filename);

    fp_out = fopen(out_filename, "w");
    if (fp_out == NULL) {
        printf("无法创建输出文件。\n");
        return 1;
    }

    for (int i = 0; i < 5; i++) {
        int idx = lucky_indices[i];
       
        printf("%s\n", students[idx]);
    
        fprintf(fp_out, "%s\n", students[idx]);
    }
    
    fclose(fp_out);
    printf("中奖名单已成功写入文件 %s\n", out_filename);

    return 0;
}

//预览结果如图所示