实验五

Task 1.1

#define _CRT_SECURE_NO_WARNINGS
#include  <stdio.h>
#include <stdlib.h>
#define N 5
#define M 80
typedef struct
{
    char name[M];
    char author[M];
}Book;
int main()
{
    Book x[N] = { {"一九八四","乔治.奥威尔"},
                  {"美丽新世界","赫胥黎"},
                  {"昨日的世界","斯蒂芬.茨威格"},
                  {"万历十五年","黄仁宇"},
                  {"一只特立独行的猪","王小波"}
                };
    int i;
    FILE* fp;
    fp = fopen("data1.txt", "w");
    if (fp == NULL)
    {
        printf("fail to open file\n");
        return 1;
    }
    for (i = 0; i < N; ++i)
    {
        fprintf(fp, "%-20s %-20s\n", x[i].name, x[i].author);
        printf("%-20s %-20s\n", x[i].name, x[i].author);
    }
    fclose(fp);
    return 0;
}

Task 1.2

#define _CRT_SECURE_NO_WARNINGS
#include  <stdio.h>
#include <stdlib.h>
#define N 5
#define M 80
typedef struct
{
    char name[M];
    char author[M];
}Book;
int main()
{
    Book x[N];
    int i;
    FILE* fp;
    fp = fopen("data1.txt", "r");
    if (fp == NULL)
    {
        printf("fail to open file\n");
        return 1;
    }
    for (i = 0; i < N; ++i)
    {
        fscanf(fp, "%s %s\n", x[i].name, x[i].author);
        printf("%-20s %-20s\n", x[i].name, x[i].author);
    }
    fclose(fp);
    return 0;
}

问题：因为x[i].name和x[i].author是数组，数组名本身指向的就是这个数组的首地址，不需要地址符。

Task 2.1

#define _CRT_SECURE_NO_WARNINGS
#include  <stdio.h>
#include <stdlib.h>
#define N 5
#define M 80
typedef struct
{
    char name[M];
    char author[M];
}Book;
int main()
{
    Book x[N] = { {"一九八四", "乔治.奥威尔"},
                  {"美丽新世界", "赫胥黎"},
                  {"昨日的世界", "斯蒂芬.茨威格"},
                  {"万历十五年", "黄仁宇"},
                  {"一只特立独行的猪", "王小波"}
                };
    int i;
    FILE* fp;
    fp = fopen("data2.dat", "wb");
    if (fp == NULL)
    {
        printf("fail to open file\n");
        return 1;
    }
    fwrite(x, sizeof(Book), N, fp);
    fclose(fp);
    return 0;
}

1.正确生成

2.不直观

Task 2.2

#define _CRT_SECURE_NO_WARNINGS
#include  <stdio.h>
#include <stdlib.h>
#define N 5
#define M 80
typedef struct
{
    char name[M];
    char author[M];
}Book;
int main()
{
    Book x[N];
    int i;
    FILE* fp;
    fp = fopen("data2.dat", "rb");
    if (fp == NULL)
    {
        printf("fail to open file\n");
        return 1;
    }
    fread(x, sizeof(Book), N, fp);
    for (i = 0; i < N; ++i)
    {
        printf("%-20s%-20s\n", x[i].name, x[i].author);
    }
    fclose(fp);
    return 0;
}

Task 3.2

 

#define _CRT_SECURE_NO_WARNINGS
#include  <stdio.h>
int main()
{
    FILE* fin;
    int count = 0;
    char ch;
    fin = fopen("data3_1.txt", "r");
    if (fin == NULL)
    {
        printf("fail to open data3_1.txt\n");
        return 1;
    }
    while (!feof(fin))
    {
        ch = fgetc(fin);
        if (ch == ' ' || ch == '\n'|| ch==EOF)
        {
            continue;
        }
        count++;
    }
    fclose(fin);
    printf("data3_1.txt中共包含字符数:%d", count);
    return 0;
}

Task 5

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define N 10

typedef struct
{
    long int id;
    char name[20];
    float objective;  /*客观题得分*/
    float subjective; /*操作题得分*/
    float sum;
    char level[10];
} STU;

// 函数声明
void input(STU s[], int n);
void output(STU s[], int n);
void process(STU s[], int n);

int main()
{
    STU stu[N];

    printf("从文件读入%d个考生信息: 准考证号，姓名，客观题得分(<=40)，操作题得分(<=60)\n", N);
    input(stu, N);

    printf("\n对考生信息进行处理: 计算总分，确定等级\n");
    process(stu, N);

    printf("\n打印考生完整信息, 并保存到文件中");
    output(stu, N);

    return 0;
}

// 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 input(STU s[], int n)
{
    int i;
    FILE* fin;

    fin = fopen("examinee.txt", "r");
    if (fin == NULL)
    {
        printf("fail to open file\n");
        exit(0);
    }

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

    fclose(fin);
}

//输出考生完整信息: 准考证号，姓名，客观题得分，操作题得分，总分，等级
// 不仅输出到屏幕上，还写到文本文件result.txt中
void output(STU s[], int n)
{
    FILE* fout;
    int i;

    // 输出到屏幕
    printf("\n");
    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等级\n");
    for (i = 0; i < n; i++)
        printf("%ld\t\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].level);

    // 保存到文件 
    fout = fopen("result.txt", "w");
    if (!fout)
    {
        printf("fail to open or create result.txt\n");
        exit(0);
    }

    fprintf(fout, "准考证号\t\t姓名\t客观题得分\t操作题得分\t总分\t\t等级\n");

    for (i = 0; i < n; i++)
        fprintf(fout, "%ld\t\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].level);

    fclose(fout);
}

// 对考生信息进行处理：计算总分，排序，确定等级
void process(STU s[], int n)
{
    STU pointer;
    int i, j, k;
    for (i = 0; i < n; i++)
    {
        s[i].sum = s[i].objective + s[i].subjective;
    }
    for (j = 0; j < n; j++)
    {
        for (k = 0; k <= j; k++)
        {
            if (s[k].sum < s[j].sum)
            {
                pointer = s[k];
                s[k] = s[j];
                s[j] = pointer;
            }
        }
    }
    for (i = 0; i < 1; i++) 
    { 
        strcpy(s[i].level, "优秀");
    }
    for (; i >= 1 && i < 5; i++)
    {
        strcpy(s[i].level, "合格");
    }
    for (; i < n; i++)
    {
        strcpy(s[i].level, "不合格");
    }
}

Task 6

 

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<time.h>
#include<stdlib.h>
#define N 80
struct student
{
    char id[20];
    char name[20];
    char grade[20];
};
int main()
{
    struct student std[N];
    int i, t;
    FILE* fin, * fout;
    srand(time(0));
    fin = fopen("list.txt", "r");
    if (fin == NULL)
    {
        printf("fail to open\n");
        exit(1);
    }
    fout = fopen("lucky.txt", "w");
    if (fout == NULL)
    {
        printf("fail to creat\n");
        exit(2);
    }
    for (i = 0; i < N; i++)
    {
        fscanf(fin, "%s %s %s", std[i].id, std[i].name, std[i].grade);
    }
    for (i = 0; i < 5; i++)
    {
        t = rand() % 80;
        printf("%-20s %-20s %-20s\n", std[t].id, std[t].name, std[t].grade);
        fprintf(fout, "%-20s %-20s %-20s\n", std[t].id, std[t].name, std[t].grade);
    }
    fclose(fin);
    fclose(fout);
    return 0;
}