实验7

task4

#include <stdio.h>
#include <ctype.h>

int main() {
    FILE *file;
    char filename[] = "data4.txt";
    char ch;
    int line_count = 0;
    int char_count = 0;
    
    file = fopen(filename, "r");
    if (file == NULL) {
        printf("无法打开文件 %s\n", filename);
        return 1;
    }
    
    int is_new_line = 1;  
    
    while ((ch = fgetc(file)) != EOF) {
        if (ch == '\n') {
            line_count++;
            is_new_line = 1;
        } else {
            if (!isspace(ch)) {
                char_count++;
            }
            is_new_line = 0;
        }
    }
    
    if (!is_new_line) {
        line_count++;
    }
    
    fclose(file);
    
    printf("data4.txt统计结果：\n");
    printf("行数：                  %d\n", line_count);
    printf("字符数(不计空白符)：    %d\n", char_count);
    
    return 0;
}

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task5

#include <stdio.h>
#include <string.h>
#define N 10

typedef struct {
    long id;            
    char name[20];      
    float objective;    
    float subjective;   
    float sum;        
    char result[10];    
} STU;

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);   
    write(stu, cnt);  
    
    pass_rate = 1.0 * cnt / N;
    printf("\n本次等级考试通过率: %.2f%%\n", pass_rate*100);
    
    return 0;
}

void output(STU st[], int n) {
    int i;
    
    printf("准考证号\t姓名\t\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%-10s\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);
}

void read(STU st[], int n) {
    int i;
    FILE *fin;
    fin = fopen("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);
}

void write(STU s[], int n) {
    int i;
    FILE *fout;
    
    fout = fopen("list_pass.txt", "w");
    if (!fout) {
        printf("fail to open file list_pass.txt\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\t结果\n");
    
    for (i = 0; i < n; i++) {
        fprintf(fout, "%ld\t\t%-10s\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].result);
    }
    
    fclose(fout);
}

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

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task6

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

#define N 100
#define M 5 

int main(){
    char s[N][N];        
    int has_hit[N] = {0};  
    char hit[M][N];      
    FILE *fin, *fout;
    int i, n, lucky_i;
    char filename[80];
    
    fin = fopen("list.txt", "r");
    if(!fin){
        perror("list.txt");
        return 1;
    }
    
    i = 0;
    while(fgets(s[i], N, fin) != NULL && i < N) {
        s[i][strcspn(s[i], "\n")] = 0;
        s[i][strcspn(s[i], "\r")] = 0;
        i++;
    }
    n = i;  

    printf("输入文件名：");
    fgets(filename, sizeof(filename), stdin);
    filename[strcspn(filename, "\n")] = 0; 
    
    srand(time(0));
    
    int selected_count = 0;
    while(selected_count < M){
        lucky_i = rand() % n;
        
        if(has_hit[lucky_i])  
            continue;
        
        has_hit[lucky_i] = 1;
        strcpy(hit[selected_count], s[lucky_i]);  
        selected_count++;
    }
    
    fout = fopen(filename, "w");
    if(!fout){
        perror(filename);
        fclose(fin);
        return 1;
    }
    
    printf("\n------------中奖名单------------\n");
    for(i = 0; i < M; ++i){
        printf("%s\n", hit[i]);
    }
    printf("\n------------保存到文件------------\n");
    
    for(i = 0; i < M; ++i){
        fprintf(fout, "%s\n", hit[i]);
    }
    
    printf( "输入文件名：");
    fgets(filename, sizeof(filename), stdin);
    
    printf("保存成功！");
    
    fclose(fin);
    fclose(fout);
    
    return 0;
}

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