实验7

task4

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

int main() {
    FILE *fp;
    char filename[] = "data4.txt";
    char ch;
    int lines = 0;
    int characters = 0;

    
    fp = fopen(filename, "r");
    if (fp == NULL) {
        perror("Error opening file");
        return -1;
    }

    
    while ((ch = fgetc(fp))!= EOF) {
        if (ch!= ' ' && ch!= '\n' && ch!= '\t') {
            characters++;
        }
        if (ch == '\n') {
            lines++;
        }
    }

    
    fclose(fp);

    
    printf("data4.txt统计结果:\n");
    printf("行数: %d\n", lines + 1);
    printf("字符数(不计空白符): %d\n", characters);

    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...\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，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("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);
}

// 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 s[], int n) {
    FILE *fout;
    fout = fopen("list_pass.txt", "w");
    if (!fout) {
        printf("fail to open file\n");
        return;
    }
    for (int i = 0; i < n; i++) {
        if (strcmp(s[i].result, "通过") == 0) {
            fprintf(fout, "%ld %s %.2f %.2f %.2f %s\n", s[i].id, s[i].name, s[i].objective, s[i].subjective, s[i].sum, s[i].result);
        }
    }
    fclose(fout);
}

// 对考生信息进行处理：计算每位考生考试总分、结果；统计考试通过的人数
int process(STU st[], int n, STU st_pass[]) {
    int count = 0;
    for (int i = 0; i < n; i++) {
        st[i].sum = st[i].objective + st[i].subjective;
        if (st[i].sum >= 60) {
            st_pass[count] = st[i];
            strcpy(st[i].result, "通过");
            count++;
        } else {
            strcpy(st[i].result, "未通过");
        }
    }
    return count;
}

 task5

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


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


void swap(Student *a, Student *b) {
    Student temp = *a;
    *a = *b;
    *b = temp;
}


void randomSelect(Student students[], int n, Student selected[], int k) {
    srand((unsigned int)time(NULL));
    for (int i = 0; i < n; i++) {
        int j = rand() % (n - i) + i;
        swap(&students[i], &students[j]);
    }
    for (int i = 0; i < k; i++) {
        selected[i] = students[i];
    }
}


void display(Student students[], int n) {
    for (int i = 0; i < n; i++) {
        printf("%s %s %s\n", students[i].id, students[i].name, students[i].classInfo);
    }
}


void writeToFile(Student students[], int n, char *filename) {
    FILE *file = fopen(filename, "w");
    if (file!= NULL) {
        for (int i = 0; i < n; i++) {
            fprintf(file, "%s %s %s\n", students[i].id, students[i].name, students[i].classInfo);
        }
        fclose(file);
    } else {
        perror("无法打开文件");
    }
}

int main() {
    const int STUDENT_NUM = 80;
    Student students[STUDENT_NUM];
    Student selected[5];
    char filename[100];
    int count = 0;

   
    FILE *inFile = fopen("list.txt", "r");
    if (inFile!= NULL) {
        while (count < STUDENT_NUM && fscanf(inFile, "%s %s %s", students[count].id, students[count].name, students[count].classInfo) == 3) {
            count++;
        }
        fclose(inFile);
    } else {
        perror("无法打开文件");
        return -1;
    }
    
    printf("----------随机抽点名单----------\n") ;

    
    randomSelect(students, count, selected, 5);

    
    display(selected, 5);
    
    printf("\n----------保存到文件----------\n") ;

    
    printf("请输入文件名：");
    scanf("%s", filename);
    writeToFile(selected, 5, filename);
    printf("保存成功！") ;

    return 0;
}