实验7

task4

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>

int main()
{
    char ch;
    
    FILE* fp;
    
    int n = 0;

    fp = fopen("data4.txt", "r");//读出data4 

    ch = fgetc(fp);
    while (ch != EOF) {
        if (ch != ' '&& ch!='\n')
            ++n;
        ch = fgetc(fp);
    }

    printf("data4.txt中包含的字符数：%d", n);

    fclose(fp);

    return 0;
}

task5

#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) {
    // 补足代码
    // ×××
    int i, j;
    
    for(i = 0;i < n; i++) 
        s[i].sum = s[i].objective + s[i].subjective;

    
    for(i = 0;i < n; i++) {
    
        for(j = 0;j < n - i - 1; j++) {
            if(s[j].sum < s[j + 1].sum) {
                STU t;
                t = s[j];
                s[j] = s[j + 1];
                s[j + 1] = t;
            }
            
        }
    }
    
    
    for(i = 0;i < n; i++) {
        if(i <= n * 0.1) 
             strcpy(s[i].level, "优秀");
        else if(i <= n * 0.5) 
             strcpy(s[i].level, "合格");
        else
             strcpy(s[i].level, "不合格");
    }
    
}

task6

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define N 100
#define M 5
#define R1 1
#define R2 80

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

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

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

    input(stu, N);

    srand(time(0));
    
    for (i = 0,num=0; i < M; ++i) {
        num = rand() % (R2 - R1 + 1) + R1;
        lucky[i] = stu[num];
    }
    
    output(lucky, M);
    
    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].class);
    }

    fclose(fin);
}

void output(STU s[], int n) {
    FILE* fout;
    int i;
    
    for (i = 0; i < n; i++)
        printf("%d\t%s\t%s\n", s[i].id, s[i].name, s[i].class);

    fout = fopen("lucky.txt", "w");
    if (!fout) {
        printf("fail to open or create result.txt\n");
        exit(0);
    }

    for (i = 0; i < n; i++)
        fprintf(fout, "%d\t%s\t%s\n", s[i].id, s[i].name, &s[i].class);

    fclose(fout);
}