实验7

task4

源码

//task4

#include<stdio.h>

int main()
{
    int i = 0;
    char ch;
    FILE *fp;
    
    fp = fopen("data4.txt", "r");
    if(fp == NULL)
    {
        printf("读取失败\n");
        return 1; 
    }
    
    while(ch != EOF)
    {
        ch = fgetc(fp);
        
        if(ch <= 126 && ch >= 33)
            i++;
    }
    
    printf("data4.txt文件中字符数（不包括空白符):%d", i);
    
    return 0; 
}

结果

task5

源码

#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) 
{
    int i, j, k;
    STU temp;
    
    for(i = 0; i < n; i++)
        s[i].sum = s[i].objective + s[i].subjective;
        
    for(i = 0; i < n; i++)
    {
        k = i;
        
        for(j = i + 1; j < n; j++)
            if(s[k].sum < s[j].sum)
                k = j;
                
        temp = s[i];
        s[i] = s[k];
        s[k] = temp;
        
        if(i == 0)
            strcpy(s[i].level, "优秀");
            
        if(i > 0 && i < 5) 
            strcpy(s[i].level, "合格");
            
        if(i > 4)
            strcpy(s[i].level, "不合格");
    }
}

结果

task6

源码

//task6

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h> 
#define N 80

typedef struct 
{
    int id;
    char name[20];
    char classes[30];
} STU;

void input(STU s[], int n);
void output(STU s[], int n);
void process(STU s[], STU t[], int n);

int main()
{
    STU stu[N], lucky[N];
    int num;

    printf("从文件读入学生信息\n\n");
    input(stu, N);
    
    srand(time(NULL));
    
    while(1)
    {
        printf("请输入要抽取的学生人数：\n");
        scanf("%d", &num);
        
        if(num == 0)
            break;

        process(stu, lucky, num);
    
        printf("\n抽取完毕，正在输出。\n\n");
        output(lucky, num);
    }
    
    return 0;
}

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

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

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

    fclose(fin);
}

void output(STU s[], int n) 
{
    FILE *fout;
    int i;
    time_t timeseed;
    struct tm *now;
    char name[N] = {0};
 
    time(&timeseed);
    now = localtime(&timeseed);
    strftime(name, N, "%Y.%m.%d %H-%M-%S.txt", now);
    
    printf("\n");
    //printf("%s\n", name);
    
    printf("学号\t\t姓名\t\t班级\n");
    for (i = 0; i < n; i++)
        printf("%d\t%s\t\t%s\n", s[i].id, s[i].name, s[i].classes);
        
    printf("\n");
    
    fout = fopen(name, "w");
    if (!fout) {
        printf("fail to open or create lucky.txt\n");
        exit(0);
    }
    
    fprintf(fout, "学号\t\t姓名\t\t班级\n");
    for (i = 0; i < n; i++)
        fprintf(fout, "%d\t%s\t\t%s\n", s[i].id, s[i].name, s[i].classes);

    fclose(fout);
}

void process(STU s[], STU t[], int n)
{
    int i, k;
    STU *temp[N];
    
    for(i = 0; i < N; i++)
        temp[i] = &s[i];
    
    for( i = 0; i < n; )
    {
        k = rand()%N;
        
        if(temp[k] != NULL)
        {
            t[i++] = s[k];
            temp[k] = NULL;
        }
    }
}

结果