实验5 结构体和文件

一、实验结论

task1

task1-1

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;
}

task1-2

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("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;
}

line35，从文件中读取图书名、图书作者时，为什么x[i].name和x[i].author前面没有地址符&？
%s对应输入一个字符串，需要提供一个字符数组来存储，数组名是一个地址，不用加&取地址。

task2

task2-1

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;
}

task2-2

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("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;
}

1. 在当前路径下，生成了一个文件名为data2.dat的数据文件。
2. 用文本编辑器打开后，其内容变为一行一列的存储形式。

task3

task3-2

include<stdio.h>

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

fp=fopen("data3_1.txt","r");

if(fp==NULL)
{
printf("fail to open file\n");
return 1;
}

while(!feof(fp))
{
ch=fgetc(fp);
if(ch && ch!='\0'&&ch!=' '&&ch!='\n'&&ch!=' ')
count++;
}

fclose(fp);

printf("data3_1.txt中共包含字符数：%d",count);

return 0;
}

task5

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 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;
}

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);
}

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\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("fail to open or create result.txt\n");
exit(0);
}

fprintf(fout, "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++)
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)
{
STU t;
int i,j;

for(i=0; i<n; i++)
{
s[i].sum=s[i].objective+s[i].subjective;
}

for(i=0; i<n; i++)
for(j=0;j<n-i-1;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+1)<=n*0.1)
strcpy(s[i].level,"优秀");

else if((i+1)>n0.1&&(i+1)<=n0.5)
strcpy(s[i].level,"合格");

else
strcpy(s[i].level,"不合格");
}
}

task6

include<stdio.h>

include<time.h>

include<stdlib.h>

define N 5

define M 80

typedef struct
{
long int id;
char name[M];
char clas[M];
}STU;

int main()
{
STU s[M];

srand(time(0));

FILE fp,fq;

fp=fopen("list.txt","r");
fq=fopen("lucky.txt","w+");

int i,j,m,q;

for(i=0;i<M;i++)
{
fscanf(fp,"%ld%s%s",&s[i].id,s[i].name,s[i].clas);
}

for(j=0;j<N;j++)
{
m=rand()%80;

for(i=0;i<M;i++)
{
if(m==s[i].id%100)
{
printf("%ld%-20s%-20s\n",s[i].id,s[i].name,s[i].clas);
fprintf(fq,"%ld\t%20s\t%20s\t\n",s[i].id,s[i].name,s[i].clas);
}
}
}

fclose(fp);
fclose(fq);

return 0;
}