Đề bài là quản li cán bộ phòng nhân sự, mọi người xem e sai chỗ nào vậy

#include <stdio.h>
#include <string.h>

char ss[80];

typedef struct {
    int ngay;
    int thang;
    int nam;}date;

    typedef struct
    {
        char ten[80];
        int so_nha;
        char pho[80];
        char thanh_pho[80];
        float luong;
        date ngaysinh;
    }mau_nhan_su;

    mau_nhan_su read_screen(mau_nhan_su Nguoi);
    mau_nhan_su lish(mau_nhan_su Nguoi);
    mau_nhan_su update(mau_nhan_su Nguoi);

    FILE *fpt;
    mau_nhan_su Nguoi;
int main()
{
    for(;;)
    {int flag=1;
    mau_nhan_su Nguoi;
    printf("menu:
-1.add
-2.lish
-3.update
");
    scanf("%d",&flag);

    Nguoi.luong=0;
    switch (flag)
    {case 1:
    while(flag)
    {
        fpt=fopen("nhan_su.DAT","ab");
        printf("
ten: ");
        gets(Nguoi.ten);
        if (Nguoi.ten[0]=='') break;
        Nguoi=read_screen(Nguoi);
        fwrite(&Nguoi, sizeof(mau_nhan_su), 1, fpt);
        fclose(fpt);
    }
    case 2:
        {
            fpt=fopen("nhan_su.DAT","rb");

        Nguoi=lish(Nguoi);

            fclose(fpt);

        }
    case 3:
        {
            fpt=fopen("nhan_su.DAT","r+b");

        Nguoi=update(Nguoi);
        fclose(fpt);
        }
    }
}

mau_nhan_su read_screen(mau_nhan_su Nguoi)
{
    printf("hay cho ngay/thang/nam: ");
    scanf("%d/%d/%d",&Nguoi.ngaysinh.ngay,&Nguoi.ngaysinh.thang,&Nguoi.ngaysinh.nam);
    printf("so nha: ");
    scanf("%d",&Nguoi.so_nha);
    gets(ss);
    printf("thanh pho: ");
    gets(Nguoi.thanh_pho);

    printf("luong: ");
    scanf("%f",&Nguoi.luong);
    gets(ss);
    return(Nguoi);

}

mau_nhan_su lish(mau_nhan_su Nguoi)
{
    int kt, no;
        printf("nhap phan tu muon truy nhap:");
        scanf("%d",&no);
        fseek(fpt,0,SEEK_END);
        kt=ftell(fpt);
        if (no*sizeof(mau_nhan_su)<kt && no*sizeof(mau_nhan_su)>0)
        {
            fseek(fpt,no*sizeof(mau_nhan_su),0);
            fread(&Nguoi,sizeof(mau_nhan_su),1,fpt);
    printf("brithday: %d/%d/%d",&Nguoi.ngaysinh.ngay,&Nguoi.ngaysinh.thang,&Nguoi.ngaysinh.nam);
    printf("so nha : %d",Nguoi.so_nha);
    printf("thanh pho : %s",Nguoi.thanh_pho);

    printf("luong: %f",&Nguoi.luong);


        } else printf("ko co pt!");
        return(Nguoi);
}



mau_nhan_su update(mau_nhan_su Nguoi)
{
    int kt, no;
        printf("nhap phan tu muon truy nhap:");
        scanf("%d",&no);
        fseek(fpt,0,SEEK_END);
        kt=ftell(fpt);
        if (no*sizeof(mau_nhan_su)<kt && no*sizeof(mau_nhan_su)>0)
        {
            fseek(fpt,no*sizeof(mau_nhan_su),0);
            fread(&Nguoi,sizeof(mau_nhan_su),1,fpt);
    printf("brithday: %d/%d/%d",&Nguoi.ngaysinh.ngay,&Nguoi.ngaysinh.thang,&Nguoi.ngaysinh.nam);
    printf("so nha : %d",Nguoi.so_nha);
    printf("thanh pho : %s",Nguoi.thanh_pho);
    printf("
");
    printf("luong: %f",&Nguoi.luong);
    printf("hay cho ngay/thang/nam: ");
    scanf("%d/%d/%d",&Nguoi.ngaysinh.ngay,&Nguoi.ngaysinh.thang,&Nguoi.ngaysinh.nam);
    printf("so nha: ");
    scanf("%d",&Nguoi.so_nha);
    gets(ss);
    printf("thanh pho: ");
    gets(Nguoi.thanh_pho);

    printf("luong: ");
    scanf("%f",&Nguoi.luong);
    gets(ss);
    
    } else printf("ko co pt!");
    return(Nguoi);
}