C语言学习笔记七

任务四

简单文件读写

源码

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

int main()
{
    FILE *fp;
    char ch;
    int character = 0;
    int line = 0;

    fp = fopen("data4.txt", "r");
    if (fp == NULL)
    {
        printf("fail to open\n");
        return 1;
    }

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

    if (ftell > 0 && ch != '\n')
        line++;

    printf("Total lines: %d\n", line);
    printf("Total characters: %d\n", character);

    fclose(fp);
    return 0;
}

结果

任务五

文件综合应用 考试

源码

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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("Add %d students from file...\n", N);
    read(stu, N);

    printf("\nFiguring...\n");
    cnt = process(stu, N, stu_pass);

    printf("\nStudents passed the exam:\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("\nPass Rank: %.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("Number\tName\tObj_Score\tOpe_Score\tTotal_Score\tResult\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;
    }

    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 st[], int n)
{
    int i, cnt = 0;
    FILE *fp;

    fp = fopen("list_pass.txt", "w");
    if (fp == NULL)
    {
        printf("fail to open\n");
        return;
    }

    for (i = 0; i < n; i++)
    {
        if (st[i].sum >= 60)
        {
            cnt++;
            fprintf(fp, "%ld %s %.2f %.2f %.2f %s\n", st[i].id, st[i].name, st[i].objective, st[i].subjective, st[i].sum, st[i].result);
        }
    }

    fclose(fp);

    printf("%d students passed the exam\n", cnt);
}

// 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)
        {
            cnt++;
            strcpy(st[i].result, "Passed");
            strcpy(st_pass[cnt - 1].name, st[i].name);
            st_pass[cnt - 1].id = st[i].id;
            st_pass[cnt - 1].objective = st[i].objective;
            st_pass[cnt - 1].subjective = st[i].subjective;
            st_pass[cnt - 1].sum = st[i].sum;
            strcpy(st_pass[cnt - 1].result, st[i].result);
        }
        else
        {
            strcpy(st[i].result, "Failed");
        }
    }

    return cnt;
}

结果

任务六

文件综合应用 点名

源码

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

#define M 100

typedef struct
{
    int id;
    char name[20];
    char class[100];
} STU;

void shuffle(char *str[], int n)
{
    for (int i = n - 1; i > 0; i--)
    {
        int j = rand() % (i + 1);
        char *temp = str[i];
        str[i] = str[j];
        str[j] = temp;
    }
}

void sort(char *str[], int n)
{
    STU stu[M];
    for (int i = 0; i < n; i++)
    {
        if (sscanf(str[i], "%d\t%s\t%s", &stu[i].id, stu[i].name, stu[i].class) != 3)
        {
            printf("Error parsing string: %s\n", str[i]);
            return;
        }
    }
    for (int i = 0; i < n - 1; i++)
    {
        for (int j = i + 1; j < n; j++)
        {
            if (stu[i].id > stu[j].id)
            {
                STU temp = stu[i];
                stu[i] = stu[j];
                stu[j] = temp;
            }
        }
    }
    for (int i = 0; i < n; i++)
    {
        snprintf(str[i], M, "%d\t%s\t%s", stu[i].id, stu[i].name, stu[i].class);
    }
}

void save_to_file(char *str[], int n)
{
    printf("# press \"c\" to set a custom file name\n");
    printf("# press any other key to use default file name\n\n");
    printf("choice: ");
    char choice;
    char filename[100];
    FILE *fp;
    scanf(" %c", &choice);

    if (choice == 'c')
    {
        printf("enter a file name: ");
        scanf("%99s", filename);
        fp = fopen(filename, "w");
    }
    else
    {
        time_t t = time(NULL);
        strftime(filename, sizeof(filename), "%Y-%m-%d_%H-%M-%S.txt", localtime(&t));
        fp = fopen(filename, "w");
    }

    if (fp == NULL)
    {
        printf("\nfail to open\n");
        return;
    }

    for (int i = 0; i < n; i++)
    {
        if (fprintf(fp, "%s\n", str[i]) < 0)
        {
            printf("Error\n");
            break;
        }
    }

    fclose(fp);
    printf("\nfile saved as %s\n", filename);
}

int main()
{
    FILE *fp = fopen("list.txt", "r");
    if (fp == NULL)
    {
        printf("fail to open\n");
        return 1;
    }

    char *data[M];
    int cnt = 0;

    while (cnt < M && !feof(fp))
    {
        data[cnt] = malloc(M * sizeof(char));
        if (fgets(data[cnt], M, fp) != NULL)
        {
            data[cnt][strcspn(data[cnt], "\n")] = 0;
            cnt++;
        }
        else
        {
            free(data[cnt]);
            cnt--;
        }
    }
    fclose(fp);

    srand(time(NULL));
    shuffle(data, cnt);

    printf("---------\tRandom Picking\t---------\n\n");
    char *picked[5];
    for (int i = 0; i < 5; i++)
        picked[i] = data[i];

    sort(picked, 5);

    for (int i = 0; i < 5; i++)
        printf("%s\n", picked[i]);

    printf("\n\n---------\tSave to File\t---------\n\n");

    save_to_file(picked, 5);

    for (int i = 0; i < cnt; i++)
        free(data[i]);

    return 0;
}

结果




__EOF__\_\_EOF\_\_


学习笔记
#C语言
C语言学习笔记七
https://churk.top/2024/12/30/2024-12-30-01/
作者
Churk Ben
发布于
2024年12月30日
许可协议