第七次作业

task4

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

int main() {
    FILE *fp = fopen("data4.txt", "r");
    if (fp == NULL) {
        perror("无法打开文件");
        return 1;
    }

    int lines = 0;
    int count = 0;
    int has_char = 0;  
    int c;

    while ((c = fgetc(fp)) != EOF) {
        if (c == '\n') {
            lines++;
            has_char = 0; 
        } else if (c == ' ' || c == '\t' || c == '\r') {
            has_char = 1; 
        } else {
            count++;       
            has_char = 1;  
        }
    }

    if (has_char) {
        lines++;
    }

    fclose(fp);

    printf("data4.txt统计结果：\n");
    printf("行数：%21d\n", lines);
    printf("字符数（不计空白符）：%6d\n", count);

    return 0;
}

task5 

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

#define N 10

typedef struct {
    long id;            // 准考证号
    char name[20];      // 姓名
    float objective;    // 客观题得分
    float subjective;   // 操作题得分
    float sum;          // 总分
    char result[10];    // 考试结果
} STU;

// 函数声明
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);   // 输出所有考生完整信息到屏幕
    write(stu, N);    // 输出考试通过的考生信息到文件

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

    return 0;
}

// 把所有考生完整信息输出到屏幕上
// 准考证号，姓名，客观题得分，操作题得分，总分，结果
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);
}

// 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 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 s[], int n) {
    FILE *fout = fopen("list_pass.txt", "w");
    if (!fout) {
        printf("fail to create 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   结果\n");
    
    int i;
    for (i = 0; i < n; i++) {
        fprintf(fout, "%ld\t  %s\t    %.2f\t          %.2f\t        %.2f\t   %s\n", 
               s[i].id, s[i].name, s[i].objective,
               s[i].subjective, s[i].sum, s[i].result);
    }
    
    fclose(fout);
    printf("考试通过的考生信息已写入文件 list_pass.txt\n");
}

int process(STU st[], int n, STU st_pass[]) {
    int pass_count = 0;
    int 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");
            st_pass[pass_count++] = st[i];
        } else {
            strcpy(st[i].result, "不通过");
        }
    }
    
    return pass_count; 
}

 

 

 task 6:

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

#define MAX_PARTICIPANTS 100
#define WINNER_COUNT 5

typedef struct {
    char id[20];        // 学号
    char name[20];      // 姓名
    char class[50];     // 班级
} Participant;

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

    Participant participants[MAX_PARTICIPANTS];
    int count = 0;
    int i; 
    
    while (fscanf(inputFile, "%s %s %[^\n]", participants[count].id, 
                  participants[count].name, participants[count].class) == 3) {
        count++;
        if (count >= MAX_PARTICIPANTS) break;
    }
    fclose(inputFile);

    if (count < WINNER_COUNT) {
        printf("参与者数量不足，无法抽取 %d 个获奖者\n", WINNER_COUNT);
        return 1;
    }

    srand(time(NULL));

    int selected[count];
    for (i = 0; i < count; i++) {
        selected[i] = 0; 
    }

    int winners[WINNER_COUNT];
    int winnerCount = 0;
    
    while (winnerCount < WINNER_COUNT) {
        int index = rand() % count; 
        
        if (!selected[index]) {
            selected[index] = 1;     
            winners[winnerCount] = index;
            winnerCount++;
        }
    }

    printf("\n------------中奖名单------------\n");
    for (i = 0; i < WINNER_COUNT; i++) {
        int idx = winners[i];
        printf("%s\t%s\t%s\n", participants[idx].id, 
              participants[idx].name, participants[idx].class);
    }

    char outputFilename[100];
    printf("\n------------保存到文件------------\n");
    printf("输入文件名：") ; 
    scanf("%s", outputFilename);

    FILE *outputFile = fopen(outputFilename, "w");
    if (!outputFile) {
        printf("无法创建文件 %s\n", outputFilename);
        return 1;
    }
    

    for (i = 0; i < WINNER_COUNT; i++) {
        int idx = winners[i];
        fprintf(outputFile, "%s\t%s\t%s\n", participants[idx].id, 
                participants[idx].name, participants[idx].class);
    }
    fclose(outputFile);
    
    printf("\n保存成功！\n", outputFilename);

    return 0;
}