实验7

任务4

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define N 100


int main()
{
    FILE *fp;
    int ch, cnt = 0, k = 0;
    fp = fopen("data4.txt", "r");
    if (fp == NULL) 
    {
        printf("无法打开文件\n");
        return 1;
    }
    
    while ((ch = fgetc(fp))!= EOF) 
    {
        if (ch == '\n') 
        {
            cnt++;
        } 
        else if (ch!= ' ' && ch!= '\t') 
            k++;
    }

    if (ch!= '\n' && k > 0) {
        cnt++;
    }
    fclose(fp);
    printf("data4.txt统计结果：\n");
    printf("行数: %d\n", cnt);
    printf("字符数(不计空格符): %d\n", k);

    

    return 0;
}
    
    
    
    

 

任务5

#include <stdio.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 st_pass[]);

int main() {
    STU stu[N], stu_pass[N];
    int cnt;
    double pass_rate;

    printf("从文件读入%d个考生信息...\n", N);
    read(stu, N);

    printf("\n对考生成绩进行统计...\n");
    cnt = process(stu, N, stu_pass);

    printf("\n通过考试的名单:\n");
    output(stu, N);   
    write(stu, N);  

    pass_rate = 1.0 * cnt / N;
    printf("\n本次等级考试通过率: %.2f%%\n", pass_rate*100);

    return 0;
}


void output(STU st[], int n) {
    int i;
    
    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=0;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 read(STU st[], int n) {
    int i;
    FILE *fin;

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

    while (!feof(fin)) {
        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 write(STU st[], int n) 
{
    FILE *fout;
    int i;

    fout=fopen("list_pass.txt", "w");
    if (!fout) {
        printf("fail to open file\n");
        return;
    }

    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结果\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", 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 st_pass[]) 
{
    int i, cnt=0;

    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");
            st_pass[cnt++] = st[i];

        } else 
            strcpy(st[i].result,"不通过");
        
    }

    return cnt;
    
}

 

任务6

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>

#define N 80
#define M 5

// 学生结构体
typedef struct 
{
    char id[N];
    char name[N];
    char class[N];
} Stu;

// 从文件读取学生数据
void read(Stu s[], const char *fn) 
{
    FILE *fp =fopen(fn,"r");
    int i;
    if (fp==NULL) 
    {
        printf("无法打开文件");
        return 1;
    }
    for (i=0;i<N;i++) {
        fscanf(fp, "%s %s %s",s[i].id,s[i].name,s[i].class);
    }
    fclose(fp);
}

// 随机抽取学生
void pick(Stu a[],Stu s[],int m) 
{
    srand(time(0));
    int used[N]={0};
    int i,idx;
    for (i=0;i<m;i++) 
    {
       
        do {
            idx = rand() % N;
        } while (used[idx]);
        used[idx] = 1;
        strcpy(s[i].id, a[idx].id);
        strcpy(s[i].name, a[idx].name);
        strcpy(s[i].class, a[idx].class);
    }
}

// 在屏幕显示抽取的学生
void show(Stu s[], int m) 
{
    int i;
    printf("抽取的学生信息如下：\n");
    for (i=0;i<m;i++) 
        printf("学号：%s，姓名：%s，班级：%s\n", s[i].id, s[i].name, s[i].class);
    
}

// 将抽取的学生写入文件
void write(Stu s[], int m, const char *fn) 
{
    int i;
    FILE *fp = fopen(fn, "w");
    if (fp==NULL) {
        printf("无法打开文件");
        return 1;
    }
    for (i=0;i<m;i++) {
        fprintf(fp, "学号：%s，姓名：%s，班级：%s\n", s[i].id, s[i].name, s[i].class);
    }
    fclose(fp);
}

int main() 
{
    Stu all[N];
    Stu select[M];
    char fileName[100];

    read(all, "list.txt");
    pick(all, select, M);
    show(select, M);

    printf("请输入要写入的文件名: ");
    scanf("%s", fileName);
    write(select, M, fileName);
    printf("\n文件保存成功！");

    return 0;
}