实验七

任务4

#include <stdio.h>

int main()
{
FILE *fp;
fp = fopen("data4.txt", "r");
int n,c;
if(fp == NULL)
{
printf("fail to open file\n");
return 1;
}
while((c = fgetc(fp)) != EOF)
{
if(c != ' ' && c != '\t' && c != '\n' && c != '\r')
{
n++;
}
}
printf("包含字符数：%d\n",n);
fclose(fp);
return 0;
}

任务5

#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;
double m;
STU a[N];
for(i=0;i<n;i++)
{
s[i].sum=s[i].objective+s[i].subjective;
}
for(j=n;j>0;j--)
{
for(i=0;i<j;i++)
{
if(s[i].sum<s[i+1].sum)
{
a[0]=s[i];
s[i]=s[i+1];
s[i+1]=a[0];
}
}
}
for(i=0;i<n;i++)
{
m=(i+1)/10.00;
if(m<=0.5)
{
if(m<=0.1)
strcpy(s[i].level,"优秀");
else
strcpy(s[i].level,"合格");
}
else
strcpy(s[i].level,"不合格");
}
}

 任务6

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

#define M 80
#define N 5

typedef struct {
    int num;
    char name[20];
    char class[20];
} STU;

int main() {
    STU s[M];
    int n = 0, i, j;
    FILE *fp = fopen("list.txt", "r");
    if (fp == NULL) {
        printf("Failed to open file list.txt\n");
        return 1;
    }
    while (fscanf(fp, "%d%s%s", &s[n].num, s[n].name, s[n].class) != EOF) {
        n++;
        if (n >= M) {
            break;
        }
    }
    fclose(fp);
    int lucky[N];
    srand((unsigned int)time(NULL));
    for (i = 0; i < N; i++) {
        lucky[i] = rand() % n;
        for (j = 0; j < i; j++) {
            if (lucky[j] == lucky[i]) {
                i--;
                break;
            }
        }
    }
    fp = fopen("lucky.txt", "w");
    if (fp == NULL) {
        printf("Failed to open file lucky.txt\n");
        return 1;
    }
    printf("Lucky students:\n");
    for (i = 0; i < N; i++) {
        int m = lucky[i];
        printf("%d %s %s\n", s[m].num, s[m].name, s[m].class);
        fprintf(fp, "%d %s %s\n", s[m].num, s[m].name, s[m].class);
    }
    fclose(fp);
    return 0;
}