实验7 文件应用编程

实验7

实验任务4

task4.c

代码：

#include <stdio.h>
#define N 100

int main() {
    
    
    int lines = 0;
    int chars = 0;
    int i,j;
    char info[N][N];
    FILE* fp;
    fp = fopen("d:\\data4.txt", "r");
    if (!fp) {
        printf("fail to open file to read");
        return 1;
    }
    i = 0;
    while (i < N && fgets(info[i], N, fp) != NULL) {
        lines++;
        i++;
    }
    fclose(fp);
  
    for (i = 0; i < lines; i++) {
        for (j = 0; info[i][j] != '\0'; j++) {
            if (info[i][j] != ' ' &&
                info[i][j] != '\t' &&
                info[i][j] != '\n' &&
                info[i][j] != '\r') {
                chars++;
            }
        }
    }
    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);
    return 0;
}

运行结果：

实验任务5

task5.c

代码：

#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("d:\\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* fl;
    fl = fopen("list_pass.txt", "w");
    if (!fl) {
        printf("fail to open file\n");
        return;
    }
    
    fprintf(fl, "%-10s\t%-10s\t%-15s\t%-15s\t%-10s\t%-10s\n",
        "准考证号", "姓名", "客观题得分", "操作题得分", "总分", "结果");
    for (int i = 0; i < n; i++) {
        
        fprintf(fl, "%-15ld\t%-10s\t%-15.2f\t%-15.2f\t%-10.2f\t%-10s\n",s[i].id, s[i].name, s[i].objective, s[i].subjective, s[i].sum, s[i].result);
    }
    fclose(fl);
}

// 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 pscount = 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");
                
                st_pass[pscount] = st[i];
                pscount++;
            }
            else {
                strcpy(st[i].result, "未通过");
            }
        }
        return pscount;
    }

运行结果：

实验任务6

task6.c

代码：

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 80

int main() {
    char info[N][80];
    char outFL[N];
    int flag[N] = { 0 };
    int i,idx;
    int lucky_index;
    int lucky_indices[5];
    FILE* fp;

    fp = fopen("d:\\list.txt", "rb");
    if (!fp) {
        printf("fail to open file to read\n");
        return 1;
    }
    for (i = 0; i < N; ++i) {
        fgets(info[i], 80, fp);
    }
    fclose(fp);

    srand(time(NULL));
    printf("------中奖名单------\n");
    for (i = 0; i < 5; ++i) {
        do {
            lucky_index = rand() % N;
        } while (flag[lucky_index]);
        flag[lucky_index] = 1;
        lucky_indices[i] = lucky_index;
        printf("%s", info[lucky_index]);
        
    }

    printf("------保存到文件------\n");
    printf("输入文件名: ");
    scanf("%s", outFL);
    fp = fopen(outFL, "w");
    if (!fp) {
        printf("fail to open file to write\n");
        return 1;
    }

    
    for (i = 0; i < 5; ++i) {
        idx = lucky_indices[i];
        fprintf(fp, "%-10s", info[idx]);
        
    }
    fclose(fp);
    printf("保存成功!\n");

    return 0;
}

运行结果：