实验7 文件应用编程

实验任务4：

源代码：

#include <stdio.h>
#include <stdlib.h>
int main()
{
    FILE* fp = fopen("data4.txt", "r");
    if (fp == NULL)
    {
        printf("文件打开失败！\n");
        return -1;
    }
    char ch;
    int line = 0;
    int charCnt = 0;
    int lastIsLine = 0;
    while ((ch = fgetc(fp)) != EOF)
    {
        if (ch == '\n' && lastIsLine == 0)
        {
            line++;
            lastIsLine = 1;
        }
        else
        {
            charCnt++;
            lastIsLine = 0;
        }
    } 
    if (lastIsLine == 0)
        line++;
    fclose(fp);
    printf("data4.txt统计结果:\n");
    printf("行数: %d\n", line);
    printf("字符数(不计空白符): %d\n", charCnt);
    system("pause");
    return 0;
}

运行截图：

 

实验任务5：

源代码：

#define _CRT_SECURE_NO_WARNINGS 
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define N 10  
typedef struct {
    long id;         
    char name[20];   
    float objective; 
    float subjective;
    float sum;      
    char result[10];  
} STU;
void read(STU st[], int n);
int process(STU st[], int n, STU st_pass[]);
void write(STU st[], int n);
void output(STU st[], int n);
int main()
{
    STU stu[N], stu_pass[N];
    int passCount;
    double passRate;
    read(stu, N);
    printf("成功读取%d位考生信息\n\n", N);
    passCount = process(stu, N, stu_pass);
    printf("===== 全部考生成绩表 =====\n");
    output(stu, N);
    write(stu_pass, passCount);
    printf("\n合格考生已保存至 list_pass.txt\n");
    passRate = 1.0 * passCount / N;
    printf("本次考试通过率：%.2f%%\n", passRate * 100);
    system("pause");
    return 0;
}
void read(STU st[], int n)
{
    FILE* fp = fopen("examinee.txt", "r");
    if (fp == NULL)
    {
        printf("examinee.txt 文件打开失败！请放到Project26根目录\n");
        system("pause");
        exit(-1);
    }
    for (int i = 0; i < n; i++)
    {
        fscanf(fp, "%ld %s %f %f", &st[i].id, st[i].name, &st[i].objective, &st[i].subjective);
    }
    fclose(fp);
}
int process(STU st[], int n, STU st_pass[])
{
    int num = 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[num++] = st[i];
        }
        else
        {
            strcpy(st[i].result, "未通过");
        }
    }
    return num;
}
void write(STU st[], int n)
{
    FILE* fp = fopen("list_pass.txt", "w");
    if (fp == NULL)
    {
        printf("文件写入失败！\n");
        return;
    }
    fprintf(fp, "%-8s %-12s %-6s %-6s %-6s %s\n", "准考证", "姓名", "客观分", "操作分", "总分", "结果");
    for (int i = 0; i < n; i++)
    {
        fprintf(fp, "%-8ld %-12s %-6.1f %-6.1f %-6.1f %s\n",
            st[i].id, st[i].name, st[i].objective, st[i].subjective, st[i].sum, st[i].result);
    }
    fclose(fp);
}
void output(STU st[], int n)
{
    printf("%-8s %-12s %-6s %-6s %-6s %s\n", "准考证", "姓名", "客观", "操作", "总分", "结果");
    for (int i = 0; i < n; i++)
    {
        printf("%-8ld %-12s %-6.1f %-6.1f %-6.1f %s\n",
            st[i].id, st[i].name, st[i].objective, st[i].subjective, st[i].sum, st[i].result);
    }
}

运行截图：

 

实验任务6：

源代码：

#define _CRT_SECURE_NO_WARNINGS 
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#define MAX_STU 80
#define LEN 50
typedef struct {
    char id[20];
    char name[20];
    char cls[30];
} Student;
int main()
{
    Student stu[MAX_STU];
    int flag[MAX_STU] = { 0 }; 
    int count = 0;
    FILE* fp = fopen("list.txt", "r");
    if (!fp)
    {
        printf("list.txt打开失败\n");
        system("pause");
        return -1;
    }
    while (fscanf(fp, "%s %s %s", stu[count].id, stu[count].name, stu[count].cls) == 3)
    {
        count++;
    }
    fclose(fp);
    srand((unsigned)time(NULL));
    Student win[5];
    int winCnt = 0;
    while (winCnt < 5)
    {
        int idx = rand() % count;
        if (flag[idx] == 0)
        {
            flag[idx] = 1;
            win[winCnt++] = stu[idx];
        }
    }
    printf("--------中奖名单--------\n");
    for (int i = 0; i < 5; i++)
    {
        printf("%s %s %s\n", win[i].id, win[i].name, win[i].cls);
    }
    char filename[50];
    printf("输入保存文件名：");
    scanf("%s", filename);
    FILE* fw = fopen(filename, "w");
    if (!fw)
    {
        printf("文件保存失败！\n");
        system("pause");
        return -1;
    }
    for (int i = 0; i < 5; i++)
    {
        fprintf(fw, "%s %s %s\n", win[i].id, win[i].name, win[i].cls);
    }
    fclose(fw);
    printf("保存成功！\n");
    system("pause");
    return 0;
}

运行截图：