实验7 文件应用编程

4. 实验任务4：文件简单应用

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

void countLinesAndChars(const char *fileName) {
    FILE *fp;
    int lines = 0, chars = 0;
    int ch;
    int inWord = 0;

    fp = fopen(fileName, "r");
    if (fp == NULL) {
        printf("无法打开文件 %s\n", fileName);
        return;
    }

    while ((ch = fgetc(fp))!= EOF) {
        if (ch == '\n') {
            lines++;
            inWord = 0;
        } else if (ch!=' ' && ch!= '\t') {
            if (!inWord) {
                chars++;
                inWord = 1;
            }
        } else {
            inWord = 0;
        }
    }

    // 处理最后一行没有换行符的情况
    if (inWord) {
        lines++;
    }

    fclose(fp);

    printf("%s统计结果：\n", fileName);
    printf("行数：%d\n", lines);
    printf("字符数(不计空白符)：%d\n", chars);
}

int main() {
    countLinesAndChars("data4.txt");
    return 0;
}

 

 

 

 

5. 实验任务5：文件综合应用

#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;

// 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_pass, cnt);  // 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%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;
    }

    i = 0;
    while (i < n && fscanf(fin, "%ld %s %f %f", &st[i].id, st[i].name, &st[i].objective, &st[i].subjective) == 4) {
        i++;
    }

    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) {
    int i;
    FILE *fout;

    fout = fopen("list_pass.txt", "w");
    if (!fout) {
        printf("fail to open file for writing\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");
    for (i = 0; i < n; i++) {
        fprintf(fout, "%ld\t%s\t%.2f\t\t%.2f\t\t%.2f\t\t%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 i, cnt = 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[cnt++] = st[i];
        } else {
            strcpy(st[i].result, "不通过");
        }
    }
    return cnt;
}

 

 

 

 

 

6. 实验任务6：文件综合应用

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

#define STUDENT_COUNT 80
#define SELECT_COUNT 5

typedef struct {
    long id;
    char name[20];
    char class[30];
} Student;

void read(Student students[]) {
    FILE *fp;
    int i = 0;
    fp = fopen("list.txt", "r");
    if (fp == NULL) {
        printf("无法打开文件list.txt\n");
        return;
    }
    while (fscanf(fp, "%ld %s %s", &students[i].id, students[i].name, students[i].class)!= EOF && i < STUDENT_COUNT) {
        i++;
    }
    fclose(fp);
}

int random(int max) {
    return rand() % max;
}

int isSelected(int selected[], int index) {
    for (int i = 0; i < SELECT_COUNT; i++) {
        if (selected[i] == index) {
            return 1;
        }
    }
    return 0;
}

void select(Student students[], Student selectedStudents[]) {
    int selected[SELECT_COUNT] = {0};
    int count = 0;
    srand((unsigned int)time(NULL));
    while (count < SELECT_COUNT) {
        int index = random(STUDENT_COUNT);
        if (!isSelected(selected, index)) {
            selected[count] = index;
            selectedStudents[count] = students[index];
            count++;
        }
    }
}

void display(Student selectedStudents[]) {
    printf("--------------随机抽点名单--------------\n");
    for (int i = 0; i < SELECT_COUNT; i++) {
        printf("%ld %s %s\n", selectedStudents[i].id, selectedStudents[i].name, selectedStudents[i].class);
    }
}

void write(Student selectedStudents[]) {
    char fileName[30];
    FILE *fp;
    printf("--------------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;
    }
    for (int i = 0; i < SELECT_COUNT; i++) {
        fprintf(fp, "%ld %s %s\n", selectedStudents[i].id, selectedStudents[i].name, selectedStudents[i].class);
    }
    fclose(fp);
    printf("保存成功！\n");
}

int main() {
    Student students[STUDENT_COUNT];
    Student selectedStudents[SELECT_COUNT];

    read(students);
    select(students, selectedStudents);
    display(selectedStudents);
    write(selectedStudents);

    return 0;
}