3.正确输出由高到低的分数顺序

生成了文本文件file.3dat

里面的数据正确并且直观可读

4.正确输出由高到低排列的学生信息

生成了二进制文件

数据不能直观读出

#include <stdio.h> 
#include <stdlib.h>
#define N 10
typedef struct student {
    int num;
    char name[20];
    int score;
}STU;

int main() {
    FILE *fin;
    STU st[N];
    int i;
    
    fin = fopen("file4.dat","rb");
    if( !fin ) {
        printf("fail to open file4.dat\n");
        exit(0);
    }
    
        fread(st,sizeof(STU),N,fin);
    
    fclose(fin);
    
    for(i=0; i<N; i++) 
        printf("%-6d%-10s%3d\n", st[i].num, st[i].name, st[i].score);
    return 0;
}

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
const int N = 10;


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


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

int main() {
    STU stu[N];
    
    printf("录入%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: 准考证号，姓名，客观题得分，操作题得分，总分，等级\n");
    output(stu, N); 
    
    return 0;
} 


void input(STU s[], int n) {
    FILE *fin;
    int i;
    fin=fopen("examinee.txt","r");
    if(!fin){
        printf("fail to open examinee.txt\n");
        exit(0);
    }
    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);
}


void output(STU s[], int n) {
    FILE *fout;
    int i;
    fout=fopen("result.txt","w");
    if(!fout){
        printf("fail to open result.txt\n");
        exit(0);
    }
    for(i=0;i<N;i++)
        fprintf(fout,"%6ld %8s %7.2f %11.2f %9.2f %4s\n",s[i].id,s[i].name,s[i].objective,s[i].subjective,s[i].sum,s[i].level);
    fwrite(s,sizeof(STU),n,fout);
    fclose(fout);
    printf("\n准考证号  姓名  客观题得分  操作题得分  总分  等级\n");
    for(i=0;i<N;i++)
        printf("%6ld %8s %7.2f %11.2f %9.2f %4s\n",s[i].id,s[i].name,s[i].objective,s[i].subjective,s[i].sum,s[i].level);
}


void process(STU s[], int n) {
    int i,j;
    STU temp;
    for(i=0;i<n;i++)
    s[i].sum=s[i].objective+s[i].subjective;
    
    for(i=0;i<n-1;i++)
      for(j=0;j<n-1-i;j++)
        if(s[j].sum<s[j+1].sum) {
            temp = s[j];
            s[j] = s[j+1];
            s[j+1] = temp;
        }
    
    for(i=0;i<n;i++)
    {
        if(i+1<=n*0.1)
          strcpy(s[i].level,"优秀");
        if(i+1>n*0.1&&i+1<=n*0.5)
          strcpy(s[i].level,"合格");
        if(i+1>n*0.5&&i+1<=n)
          strcpy(s[i].level,"不合格"); 
    }
}