#include<stdio.h>
#include<stdlib.h>
int main()
{
    int sn;
    FILE *fp;
    
    struct stu
    {
        int sno;
        int age;
        int wgt;
    };
    
    struct stu *s;
    s = (struct stu*)malloc(sizeof(struct stu));
    
    fp = fopen("law.dat", "rb");
    fread(s, sizeof(struct stu), 1, fp);
    
    printf("input student no: \n");
    fflush(stdin);
    scanf("%d", &sn);
    while(!feof(fp))
    {
        if(sn == s->sno)
        printf("%d, %d, %d\n",  s->sno, s->age, s->wgt);
        fread(s, sizeof(struct stu), 1, fp);
    }
    fclose(fp);
    return 0;
}