实验七

实验任务4

实验代码

#include <stdio.h>

int main() {
    FILE *file;
    char filename[100];
    char ch;
    int count = 0;

    file = fopen("data4.txt", "r");
    if (file == NULL) {
        printf("无法打开文件\n");
        return 1;
    }

    while ((ch = fgetc(file)) != EOF) {
        if (ch != ' ' && ch != '\n' && ch != '\t') {
            count++;
        }
    }

    fclose(file);

    printf("data4.txt中共包含字符数（不包括空白符）：%d\n", count);

    return 0;
}

实验结论

实验任务5

实验代码

#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);
}


void process(STU s[], int n) {
    int i, j;
    STU temp;
    float sum;
    float passLine10, passLine50;

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

    for (i = 0; i < n - 1; i++) {
        for (j = 0; j < n - 1 - i; j++) {
            if (s[j].sum < s[j + 1].sum) {
                temp = s[j];
                s[j] = s[j + 1];
                s[j + 1] = temp;
            }
        }
    }

    passLine10 = s[n / 10].sum;
    passLine50 = s[n / 2].sum;

    for (i = 0; i < n; i++) {
        if (s[i].sum > passLine10) {
            strcpy(s[i].level, "优秀");
        } else if (s[i].sum > passLine50) {
            strcpy(s[i].level, "合格");
        } else {
            strcpy(s[i].level, "不合格");
        }
    }
}

实验结论


实验任务6

实验代码

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

#define N 80
#define M 5

typedef struct {
    int id;
    char name[50];
    char className[50];
} Student;


int main() {
    Student students[N];
    Student luckyStudents[M];
    int numStudents = 0;

    FILE *file = fopen("list.txt", "r");
    if (file == NULL) {
        printf("无法打开文件\n");
        return 1;
    }

    while (fscanf(file, "%d %s %[^\n]", &students[numStudents].id, students[numStudents].name, students[numStudents].className) != EOF) {
        numStudents++;
    }

    fclose(file);

    srand(time(NULL));

    int i, j;
    int index;
    int selected[N] = {0};
    for (i = 0; i < M; i++) {
        index = rand() % numStudents;
        while (selected[index] == 1) {
            index = rand() % numStudents;
        }
        selected[index] = 1;
        luckyStudents[i] = students[index];
    }

    printf("随机抽取的幸运学生信息：\n");
    printf("学号\t姓名\t\t班级\n");
    for (i = 0; i < M; i++) {
        printf("%d\t%s\t\t%s\n", luckyStudents[i].id, luckyStudents[i].name, luckyStudents[i].className);
    }

    FILE *outputFile = fopen("lucky.txt", "w");
    if (outputFile == NULL) {
        printf("无法创建文件\n");
        return 1;
    }

    fprintf(outputFile, "学号\t姓名\t\t班级\n");
    for (i = 0; i < M; i++) {
        fprintf(outputFile, "%d\t%s\t\t%s\n", luckyStudents[i].id, luckyStudents[i].name, luckyStudents[i].className);
    }

    fclose(outputFile);

    return 0;
}

实验结论