#include "stdio.h"
#include "stdlib.h"
typedef struct student
{
    int num;
    char name[20];
    char s;
    int age;
}STU;
void input(STU *p)
{
    printf("请输入学号：");
    scanf("%d",&p->num);
    getchar();
    printf("请输入姓名：");
    gets(p->name);
    printf("请输入性别：");
    scanf("%c",&p->s);
    getchar();
    printf("请输入年龄：");
    scanf("%d",&p->age);
}
void save(char *filename,STU *p)
{
    FILE *fp;
    if((fp=fopen(filename,"ab"))==NULL)
    {
        fp=fopen(filename,"wb");

    }
    fwrite(p,sizeof(STU),1,fp);
    fclose(fp);
}
STU *query(char *filename,int age,STU *p)
{
    FILE *fp;
    if((fp=fopen(filename,"rb"))==NULL)
        return NULL;
    while(!feof(fp))
    {
        fread(p,sizeof(STU),1,fp);
        while(p->age<=age)
        {
            return p;
            fclose(fp);
        }
    }
    fclose(fp);
    return NULL;
}
main()
{
    char ch;
    char filename[80];
    int age;
    STU sc,*sp=&sc;
    printf("请输入文件的名字:");
    gets(filename);
    printf("是否现在输入数据(y/n):");
    ch=getchar();
    getchar();
    while(ch=='y'||ch=='Y')
    {
        input(sp);
        save(filename,sp);
        printf("\n继续(y/n):");
        ch=getchar();
        getchar();
    }
    printf("\n请输入要查询的年纪：");
    scanf("%d",&age);
    if(query(filename,age,sp)!=NULL)
    {
        printf("%-7d%-20s%-10c%-7d\n",sp->num,sp->name,sp->s,sp->age);

    }
    else
    {
        printf("\n NO result\n");
    }
}

紧急求助啊？纠结了好久

有没有高手在啊