任务三：由高到低的分数顺序正确输出

生成了文本文件file.3dat

数据正确并且可读

任务四：由高到低排列的学生信息正确输出

生成了二进制文件

数据不能读出

 

#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 <stdlib.h>
#include <string.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 *fp;
    int i;
    fp=fopen("examinee.txt","r");
    if(!fp){
        printf("fail to open examinee.txt\n");
        exit(0);
    }
    for(i=0;i<N;i++) 
        fscanf(fp,"%ld %s %f %f",&s[i].id,s[i].name,&s[i].objective,&s[i].subjective);
    fclose(fp);
}

void output(STU s[],int n){
    FILE *fp;
    int i;
    fp=fopen("result.txt","w");
    if(!fp){
        printf("fail to open result.txt\n");
        exit(0);
    }
    for(i=0;i<N;i++)
        fprintf(fp,"%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);
    fclose(fp);
    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){
    STU m;
    int i,j;
    for(i=0;i<n;i++)
        s[i].sum=s[i].objective+s[i].subjective;
    for(i=0;i<n-1;i++)
        for(j=i+1;j<n;j++)
            if(s[i].sum<s[j].sum){
                m=s[i];
                s[i]=s[j];
                s[j]=m;
            }
    char a[3][10]={"优秀","合格","不合格"}; 
    for(i=0;i<n;i++){
        if(i+1<=n/10)
            strcpy(s[i].level,a[0]);
        else if(i+1>n/10&&i<=n/2)
            strcpy(s[i].level,a[1]);
        else
            strcpy(s[i].level,a[2]); 
    }
}