一

1.代码

#include<stdio.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·奥微软"},
        {"美丽新世界","啦啦啦"},
        {"昨日的世界","斯蒂芬"},
        {"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("datal.txt", "w");
    if (fp == NULL)
    {
        printf("fail to open file\n");
        return 1;
    }
    for (i = 1; 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;
}

运行结果

2.运行代码为

#include<stdio.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("datal.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;
}

运行结果为

问题：因为是指针，本身指向地址

二运行代码

1

#include<stdio.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·奥微软"},
        {"美丽新世界","啦啦啦"},
        {"昨日的世界","斯蒂芬"},
        {"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;
}

是，是

2运行代码

#include <stdio.h>
#define N 5
#define M 80
typedef struct
{
    char name[M]; // 书名
    char author[M]; // 作者
}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;
}

三

运行代码

#include<stdio.h>
int main()
{
    FILE* fin, * fout;
    char ch;
    int i=0;
    fin = fopen("data3_1.txt", "r");
    if (fin == NULL)
    {
        printf("fail to open data3_1.txt\n");
        exit(0);
    }
    while (!feof(fin))
    {
        ch = fgetc(fin);
        if (ch != ' '&&ch!='\t'&&ch!='\n')
            i++;
    }while (!feof(fin));
    printf("%d", i-1);
    fclose(fin);
    return 0;
}

运行结果

五

运行代码

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define N 10
typedef struct
{
    long int id;
    char name[20];
    float objective;
    float subjective;
    float sum;
    char level[10];
}stu;
void input(stu s[], int n);
void output(stu s[], int n);
void process(stu s[], int n);
int main()
{
    stu st[N];
    printf("从文件读入%d个考生信息：准考证号，姓名，客观题得分，操作题得分\n", N);
    input(st, N);
    printf("\n对考生信息进行处理：计算总分，确定等级\n");
    process(st, N);
    printf("\n打印考生完整信息，并保存到文件中");
    output(st, N);
    return 0;
}
void input(stu s[], int n)
{
    int i;
    FILE* fin;
    fin = fopen("examinee.txt", "r");
    if (fin == NULL)
    {
        printf("-----");
        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);
}
void output(stu s[], int n)
{
    FILE* fout;
    int i;
    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%s\n", &s[i].id, s[i].name, s[i].objective, s[i].subjective, s[i].sum, s[i].level);
    fout = fopen("result.txt", "w");
    if (!fout)
    {
        printf("-------");
        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);
}
void process(stu s[], int n)
{
    int i = 0;
    int j = 0;
    stu t;
    for (; i < n; i++)
        s[i].sum = s[i].objective + s[i].subjective;
    for (i=0; i < n-1; i++)
        for(j=0;j<n-1-i;j++)
            if (s[j].sum < s[j + 1].sum)
            {
                t = s[j];
                s[j] = s[j + 1];
                s[j + 1] = t;
            }
    for (i = 0; i < n; i++)
    {
        if (i <= n * 0.1-1)
            strcpy(s[i].level, "优");
        else if (i > n * 0.1-1&&i<=n*0.5-1)
            strcpy(s[i].level, "合格");
        else
            strcpy(s[i].level, "不合格");
    }
}

 

运行结果

六运行代码

 

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define N 80
typedef struct
{
    long int id;
    char name[20];
    char grade[100];
}stu;
void input(stu s[], int n);
void output(stu s[], int n);
int main()
{
    stu st[N];
    printf("从文件读入%d个考生信息：学号，姓名，班级\n", N);
    input(st, N);
    printf("\n打印考生完整信息，并保存到文件中");
    output(st, N);
    return 0;
}
void input(stu s[], int n)
{
    int i;
    FILE* fin;
    fin = fopen("list.txt", "r");
    if (fin == NULL)
    {
        printf("-----");
        exit(0);
    }
    while (!feof(fin))
    {
        for (i = 0; i < n; i++)
            fscanf(fin, "%ld %s %s", &s[i].id, s[i].name, s[i].grade);
    }
    fclose(fin);
}
void output(stu s[], int n)
{
    FILE* fout;
    int i,a;
    fout = fopen("list2.txt", "w");
    if (!fout)
    {
        printf("-------");
        exit(0);
    }
    printf("\n");
    printf("准考证号\t姓名\t班级\n");
    fprintf(fout, "准考证号\t\t姓名\t班级\n");
    srand(time(0));
    for (i = 0; i < 5; i++)
    {
        a = rand() % 80;
        printf("%ld\t%s\t%s\n", s[a].id, s[a].name, s[a].grade);
        fprintf(fout, "%ld\t%s\t%s\n", s[a].id, s[a].name, s[a].grade);
    }
    fclose(fout);
}

运行结果