实验7

task1

#include<stdio.h>
#define N 80
#define M 100
typedef struct{
    char name[N];
    char author[N];
}book;
void write();
void read();
int main(){
    printf("测试1: 把图书信息写入文本文件\n");
    write();
    printf("\n测试2: 从文本文件读取图书信息, 打印输出到屏幕\n");
    read();
    return 0;
}
void write(){
    book x[] = { {"《雕塑家》", "斯科特.麦克劳德"},
                  {"《灯塔》", "克里斯多夫.夏布特"},
                  {"《人的局限性》", "塞缪尔.约翰生"}, 
                  {"《永不停步：玛格丽特.阿特伍德传》", "罗斯玛丽.沙利文"},
                  {"《大地之上》", "罗欣顿·米斯特里"}, 
                  {"《上学记》", "何兆武"}, 
                  {"《命运》", "蔡崇达"} };
    int n,i;
    FILE *fp;
    n=sizeof(x)/sizeof(x[0]);
    fp=fopen("data1.txt","w");
    if(fp==NULL){
        printf("fail to open file to write\n");
        return;
    }
    for(i=0;i<n;++i){
        fprintf(fp,"%-40s %-20s\n",x[i].name ,x[i].author );
    }
    fclose(fp);
}
void read(){
    book x[M];
    int i,n;
    FILE *fp;
    fp=fopen("data1.txt","r");
    if(fp==NULL){
        printf("fail to open file to read\n");
        return;
    }
    i=0;
    while(fscanf(fp,"%s%s",x[i].name,x[i].author )!=EOF){
        ++i;
    }
    n=i;
    for(i = 0; i < n; ++i){
        printf("%d. %-40s%-20s\n", i+1, x[i].name, x[i].author);
    }
    fclose(fp);
}

 task2

#include<stdio.h>
#define N 80
#define M 100
typedef struct{
    char name[N];
    char author[N];
}book;
void write();
void read();
int main(){
    printf("测试1: 把图书信息以数据块方式写入二进制文件\n");
    write();
    printf("\n测试2: 从二进制文件读取图书信息, 打印输出到屏幕\n");
    read();
    return 0;
}
void write(){
    book x[] = { {"《雕塑家》", "斯科特.麦克劳德"},
                  {"《灯塔》", "克里斯多夫.夏布特"},
                  {"《人的局限性》", "塞缪尔.约翰生"}, 
                  {"《永不停步：玛格丽特.阿特伍德传》", "罗斯玛丽.沙利文"},
                  {"《大地之上》", "罗欣顿·米斯特里"}, 
                  {"《上学记》", "何兆武"}, 
                  {"《命运》", "蔡崇达"} };
    int n,i;
    FILE *fp;
    n=sizeof(x)/sizeof(x[0]);
    fp=fopen("data2.dat","wb");
    if(fp==NULL){
        printf("fail to open to write\n");
        return;
    }
    fwrite(x,sizeof(book),n,fp);
    fclose(fp);
}
void read(){
    book x[M];
    int n,i;
    FILE *fp;
    fp=fopen("data2.dat","rb");
    if(fp==NULL){
        printf("fail to open to read\n");
        return;
    }
    i=0;
    while(fread(&x[i],sizeof(book),1,fp)==1){
        ++i;
    }
    n=i;
    for(i = 0; i < n; ++i)
        printf("%d. %-40s%-20s\n", i+1, x[i].name, x[i].author);
    fclose(fp);
}

task3

#include<stdio.h>
#define N 100
#define M 80
void write();
void readchar();
void readstr();
int main(){
    printf("测试1: 把一组字符信息以字符串方式写入文本文件\n");
    write();
    printf("\n测试2: 从文件以字符串方式读取, 输出到屏幕\n");
    readstr();
    printf("\n测试3: 从文件以单个字符方式读取, 输出到屏幕\n");
    readchar();
    return 0;
}
void write(){
    char *ptr[] = { "Working\'s Blues",
                    "Everything Will Flow",
                    "Streets of London",
                    "Perfect Day",
                    "Philadelphia"};
    int n,i;
    FILE *fp;
    fp=fopen("data3.txt","w");
    if(fp == NULL) {
        printf("fail to open file to write\n");
        return;
    }
    n = sizeof(ptr)/sizeof(ptr[0]);
    for(i=0;i<n;++i){
        fputs(ptr[i],fp);
        fputs("\n",fp);
    }
    fclose(fp);
}
void readstr(){
    char songs[N][M];
    int i, n;
    FILE *fp;
    fp = fopen("data3.txt", "r");
    if(fp == NULL) {
        printf("fail to open file to read\n");
        return;
    }
    i = 0;
    while(i<N&&(fgets(songs[i],M,fp)!=NULL)){
        ++i;
    }
    n=i;
    for(i=0;i<n;++i){
        printf("%d. %s",i+1,songs[i]);
    }
    fclose(fp);
}
void readchar(){
    int ch;
    FILE *fp;
    fp=fopen("data3.txt","r");
    if(fp==NULL){
        printf("fail to open file to read\n");
        return;
    }
    while((ch=fgetc(fp))!=EOF){
        putchar(ch);
    }
    fclose(fp);
}

task4

#include<stdio.h>
int main(){
    FILE *fp;
    int i,n,ch,m=0;
    fp=fopen("data4.txt","r");
    if(fp==NULL){
        printf("fail to open file to read\n");
        return;
    }
    i=0;
    while((ch=fgetc(fp))!=EOF){
        if(ch!=' '&&ch!='\n'&&ch!='\t'){
            i++;
        }
        if(ch=='\n'){
            m++;
        }
    }
    m++;
    n=i;
    fclose(fp);
    printf("data4.txt统计结果：\n");
    printf("行数:%d\n",m);
    printf("字符数（不记空白）：%d\n",n);
    return 0;
}

\为转义字符，\‘表示字符’

防止读取的内容超过数组song的容量

task5

#include<stdio.h>
#include<stdlib.h>
#include<string.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);
void write(stu st[],int n);
void output(stu st[],int n);
int process(stu st[],int n,stu stpass[]);
int main(){
    stu st[N],stpass[N];
    int cnt;
    double passrate;
    printf("从文件读入%d个考生信息...\n", N);
    read(st,N);
    printf("\n对考生成绩进行统计...\n");
    cnt =process(st,N,stpass);
    printf("\n通过考试的名单:\n");
    output(st,cnt);
    write(st,N);
    passrate=1.0*cnt/N;
    printf("\n本次等级考试通过率: %.2f%%\n", passrate*100);
    return 0;
}
void read(stu st[],int n){
    int i;
    FILE *fin;
    fin=fopen("examinee.txt","r");
    if (!fin) {
        printf("fail to open file\n");
        return;
    }
    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);
}
void output(stu st[],int n){
    int i=0;
    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结果\n");
    for(i;i<n;++i){
        printf("%ld\t\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);
    }
}
void write(stu st[],int n){
    FILE *fout;
    int i;
    fout=fopen("list_past.txt","w");
    if(!fout){
        printf("fail to open to write\n");
        return;
    }
    for(i=0;i<n;++i){
        fprintf(fout,"%ld\t\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);
    }
    fclose(fout);
}
int process(stu st[],int n,stu stpass[]){
    int cnt=0,i;
    for(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");
            stpass[cnt++]=st[i];
        }
        else
        strcpy(st[i].result,"未通过");
    }
    return cnt;
}

task6

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<time.h>
#define N 100
#define m 5
int main(){
    char s[N][N],t[N][N],name[20];
    int i=0,n,p;
    int hashit[N]={0};
    srand(time(0));
    FILE *fp1,*fp2;
    fp1=fopen("list.txt","r");
    if(!fp1){
        ferror(fp1);
        return 1;
    }
    while(fgets(s[i],N,fp1)!=NULL){
        i++;
    }
    n=i;
    fclose(fp1);
    for(i=0;i<n;++i){
        printf("%s",s[i]);
    }
    printf("-------------中奖名单-------------\n"); 
    for(i=0;i<m;++i){
        p=rand()%n;
        if(hashit[p])
        continue; 
        hashit[p]=1;
        printf("%s",s[p]);
        strcpy(t[i],s[p]);
    }
    printf("------------保存到文件-------------\n"); 
    printf("输入文件名："); 
    scanf("%s",name);
    fp2=fopen(name,"w");
    if(!fp2){
        ferror(fp2);
        return 1;
    }
    for(i=0;i<m;++i){
        fprintf(fp2,"%s\n",t[i]);
    }
    fclose(fp2);
    printf("保存成功！\n");
    return 0;
}