实验7

实验任务4:

源代码：

#include <stdio.h>

int main()
{
    FILE *fp;
    int line = 1;
    int count = 0;
    char ch;
    
    fp = fopen("data4.txt","r");
    if(fp == NULL)
    {
        printf("Fail to open file to read\n");
        return 1;
    }
    
    while((ch = fgetc(fp)) != EOF)
    {
        if(ch == '\n')
        line++;
        else if(ch != ' ' && ch != '\t')
        count++;
    }
    
    fclose(fp);
    
    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",count);
    
    return 0;
}

代码运行结果：

 实验任务5：

源代码：

#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,N);
    
    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 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 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);
}

void write(STU st[],int n)
{
    FILE *fout = fopen("list_pass.txt", "w"); 
    if (!fout) 
    {
        printf("Fail to open the list_pass\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");
    
    int i;
    for (i = 0; i < n; i++) 
    if (strcmp(st[i].result, "通过") == 0) 
    fprintf(fout, "%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(fout); 
    printf("通过考生信息已成功写入list_pass.txt\n");
}


int process(STU st[],int n,STU st_pass[])
{
    int cnt = 0; 
    for (int i = 0; i < n; i++) 
    {
        st[i].sum = st[i].objective + st[i].subjective;
        if (st[i].sum >= 60.0) 
        {
            strcpy(st[i].result, "通过"); 
            st_pass[cnt] = st[i];   
            cnt++;                  
        } 
        else 
        strcpy(st[i].result, "未通过");
    }
    
    return cnt; 
}

代码运行结果：

 实验任务6：

源代码：

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 100
#define M 5

int main()
{
    char s[N][N];
    char name[N];
    int flag[N];
    int k;
    for(k = 0;k < N;k++)
    flag[k] = 0;
    
    srand((unsigned int)time(NULL)); 
    
    FILE *fp;
    fp = fopen("list.txt","r");
    if(!fp) 
    {
        perror("list.txt");
        return 1;
    }
    
    int i;
    int n;
    i = 0;
    while(fgets(s[i],N,fp) != NULL)
    ++i;
    fclose(fp);
    n = i;
    
    int count;
    count = 0;
    while(count < M)
    {
        int j;
        j = rand() % n;  
        if(flag[j] == 0)  
        {
            flag[j] = 1;
            count++;
        }
    }
    
    printf("--------中奖名单----------\n");
    for(k = 0;k < n;k++)
    {
        if(flag[k] == 1)
        printf("%s",s[k]);
    }
    
    printf("输入文件名:");
    scanf("%s",name);
    FILE *outfp = fopen(name,"w");
    if(!outfp)
    {
        perror(name);
        return 1;
    } 
    
    for(k = 0;k < n;k++)
    {
        if(flag[k] == 1)
        fputs(s[k],outfp);
    }
       
    fclose(outfp);
    printf("保存成功");
    
    return 0;
}

代码运行结果：