实验7

4.

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

int main()
{
    int line=0,len=0;
    char ch;
    FILE *fp;

    fp=fopen("D:\\data4.txt","r");
    if(!fp){
        printf("fail to open file to read\n");
        return 0;
    }
    while((ch=fgetc(fp))!=EOF){
        if(ch=='\n')
            line++;
        if(ch!=' '&&ch!='\t'&&ch!='\n')
            len+=1;
    }
    fclose(fp);
    line++;

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

    system("pause");
    return 0;
}

 5.

#include <stdio.h>
#include <string.h>
#include <stdlib.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: 已完成\n", N);
    read(stu, N);

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

    printf("\n所有考生完整信息:\n");
    output(stu, N);   

    printf("\n通过考试的名单写入文件: 已完成!\n");
    write(stu_pass, cnt);

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

    system("pause");

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

    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);
}

// 对考生信息进行处理：计算每位考生考试总分、结果；统计并返回通过考试的人数
int process(STU st[], int n, STU st_pass[]) {
    int i,k=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[k++]=st[i];
        }
        else
            strcpy(st[i].result,"未通过");
    }

        return k;

}

// 把通过考试的考生完整信息写入文件list_pass.txt
// 准考证号，姓名，客观题得分，操作题得分，总分，结果
void write(STU st[], int n) {
    int i;
    FILE *fw;

    fw=fopen("D:\\list_pass1.txt","w");
    if(!fw){
        printf("书写失败");
        return ;
    }
    fprintf(fw,"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(fw,"%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(fw);
}

 6.

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

#define MAX 100

typedef struct {
    char id[16];
    char name[16];
    char cls[32];
}STU;

int read(STU st[], int n);
void draw_lottery(STU st[], int total, int count);
void save_to_file(STU winners[], int count);

int main(){
    STU students[MAX];
    int total;

    total=read(students, MAX);
    printf("从文件读入%d个考生信息: 已完成\n",total);

    draw_lottery(students, total, 5);

    system("pause");

    return 0;
}

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

    fin = fopen("D:\\list.txt", "r");
    if (!fin) {
        printf("fail to open file\n");
        return 0;
    }

    while(i<n&&fscanf(fin, "%s %s %[^\t\n]",
        &st[i].id,
        st[i].name,
        &st[i].cls)==3){
        i++;
    }

    fclose(fin);
    return i;
}

void draw_lottery(STU st[], int total, int count) {
    int i, index;
    int *selected;          
    STU winners[10];

    if (count > total) {
        printf("抽取人数超过总人数！\n");
        return;
    }

    selected = (int *)calloc(total, sizeof(int));
    if (!selected) {
        printf("内存分配失败！\n");
        return;
    }

    srand((unsigned)time(NULL));

    printf("\n========== 中奖名单 ==========\n");
    printf("学号\t\t姓名\t班级\n");
    printf("--------------------------------\n");

    for (i = 0; i < count; i++) {
        do {
            index = rand() % total;
        } while (selected[index] == 1);

        selected[index] = 1;
        winners[i] = st[index];

        printf("%s\t%s\t%s\n",
               winners[i].id,
               winners[i].name,
               winners[i].cls);
    }
    printf("================================\n");

    free(selected);

    save_to_file(winners, count);
}

void save_to_file(STU winners[], int count) {
    int i;
    char filename[100];
    FILE *fw;

    printf("\n请输入要保存的文件名（如：winners.txt）：");
    scanf("%s", filename);

    fw = fopen(filename, "w");
    if (!fw) {
        printf("文件创建失败！\n");
        return;
    }

    fprintf(fw, "========== 中奖名单 ==========\n");
    fprintf(fw, "学号\t\t姓名\t班级\n");
    fprintf(fw, "--------------------------------\n");
    for (i = 0; i < count; i++) {
        fprintf(fw, "%s\t%s\t%s\n",
                winners[i].id,
                winners[i].name,
                winners[i].cls);
    }
    fprintf(fw, "================================\n");

    fclose(fw);
    printf("中奖名单已保存到文件：%s\n", filename);
}