Problem(logical error) with the output of the code(file handling) - c++

Question

this is the input I made the following code for my cs project but i am facing some logical errors which i am unable to fix i tried a lot but still i am unable to fix it so please help me,,
as you can see in the picture above i entered male in sex but it is writing only ale in the file and there is a problem with the output
This is software which i made as a project for my practical exam it was working fine until my friend did some modifications to it whenever i am entering any record(using file) it is working fine(at least it seems to be) but when i am displaying the record some of the characters are missing i don't know why so please help me to fix it....*
thank you
#include<fstream.h>
#include<string.h>
#include<stdio.h>
#include<conio.h>
class patient
{
public:
int year,date,month;
int bno;
char na[20],street[20],city[20],sex[8];
patient()
{
bno=0;
year=0;
date=0;
month=0;
strcpy(na,NULL);
strcpy(city,NULL);
strcpy(street,NULL);
strcpy(sex,NULL);
}
void enterdata()
{
cout<<"\nENTER THE NAME OF THE PATIENT \t\t-----\t\t";gets(na);
cout<<"\nENTER GENDER\t\t\t\t-----\t\t";gets(sex);
cout<<"\nASSIGN A UNIQUE BED NO. \t\t-----\t\t"; cin>>bno;
cout<<"\nDATE OF BIRTH\nDATE \t\t\t\t\t-----\t\t";cin>>date;
cout<<"\nMONTH \t\t\t\t\t-----\t\t";cin>>month;
cout<<"\nYEAR \t\t\t\t\t-----\t\t";cin>>year;
cout<<"\nENTER STREET \t\t\t\t-----\t\t";gets(street);
cout<<"\nENTER CITY \t\t\t\t-----\t\t";gets(city);
}
void showdata()
{
clrscr();
cout<<" \t\t\tINFORMATION OF THE PATIENT\n";
for(int vg=0;vg<78;vg++)
cout<<"-";
cout<<"\n";
for(vg=0;vg<78;vg++)
cout<<"-";
cout<<"\n\n\t\t\tBED NO \t\t:-\t"<<bno;
cout<<"\n\n\t\t\tNAME \t\t:-\t"<<na;
cout<<"\n\n\t\t\tGENDER \t\t:-\t"<<sex;
cout<<"\n\n\t\t\tCITY \t\t:-\t"<<city;
cout<<"\n\n\t\t\tSTREET \t\t:-\t"<<street;
}
~patient()
{
bno=0;
year=0;
date=0;
month=0;
strcpy(na,NULL);
strcpy(city,NULL);
strcpy(street,NULL);
strcpy(sex,NULL);
}};
void main()
{
patient p,p1;
char ch,cna[20];
xy:
do
{
ifstream ifile;
ifile.open("file1.dat",ios::in);
ofstream ofile;
ofile.open("file1.dat",ios::app|ios::binary);
ofstream temp;
temp.open("temp1.dat",ios::app|ios::binary);
clrscr();
cout<<"\n\t\t\t***HOSPITAL MANAGEMENT SOFTWARE***"<<"\n";
cout<<"\n\t\t\t **Hospital Management Tasks**"<<"\n\n";
for(int st=0;st<80;st++)
cout<<"-";
for(st=0;st<80;st++)
cout<<"|";
for(st=0;st<80;st++)
cout<<"-";
cout<<"\n\n";
cout<<"\t\t\tPlease select a task to do...."<<"\n\n";
cout<<"\t\t\t1. Enter a new patient information ."<<"\n\n";
cout<<"\t\t\t2. View detail of existing patient ."<<"\n\n";
cout<<"\t\t\t3. Emergency"<<"\n\n";
cout<<"\t\t\t4. Discharge patient"<<"\n\n";
cout<<"\t\t\t5. Exit from the program ."<<"\n\n";
cout<<"\t\t\t6.ADMIN MODE"<<"\n\n";
cout<<"\t\t\tEnter your task serial :"<<"\n\n\t\t\t";
ch=getche();
switch(ch)
{
case '1': clrscr();
p.enterdata();
ofile.write((char*)&p,sizeof(p));
getch();
break;
case '2':
clrscr();
int k=0,cbno=0;
if(!ifile)
{
cout<<"\n unable to open file\n";
getch();
}
else
{
cout<<"\n ENTER THE NAME OF PATIENT\t\t\t-----\t\t";gets(cna);
cout<<"\n ENTER BED NUMBER\t\t\t\t-----\t\t";cin>>cbno;
ifile.clear();
ifile.seekg(0,ios::beg);
while(!ifile.eof())
{
ifile.read((char*)&p1,sizeof(p1));
if(cbno==p1.bno)
{
if(strcmpi(cna,p1.na)==0)
{
p1.showdata();
getch();
k=1;
break;
}
}
}
if(k!=1)
cout<<"\n NO SUCH RECORD PRESENT\n";
getch();
}
ifile.close();
break;
case '3':
clrscr();
temp.clear();
temp.seekp(0,ios::beg);
ifile.clear();
ifile.seekg(0,ios::beg);
p1.enterdata();
temp.write((char*)&p1,sizeof(p1));
while(!ifile.eof())
{
ifile.read((char*)&p,sizeof(p));
cout<<"\ndone writing\n";
cout<<"\n done";getch();
temp.write((char*)&p,sizeof(p));
}
ifile.close();
temp.close();
remove("file1.dat");
rename("temp1.dat","file1.dat");
break;
case '4' :
char ch;int pos=-1;
clrscr();
cout<<"\t\t\tDISCHARGE PATIENT\n";
if(!ifile)
{ clrscr();
cout<<"\n\n\t\t\t!!!!FAILED TO OPEN FILE!!!! \n";
getch();
}
else
{
cout<<"\n ENTER THE NAME OF PATIENT\t\t\t-----\t\t";gets(cna);
cout<<"\n ENTER BED NUMBER\t\t\t\t-----\t\t";cin>>cbno;
ifile.clear();
ifile.seekg(0,ios::beg);
while(!ifile.eof())
{
ifile.read((char*)&p1,sizeof(p1));
if(cbno==p1.bno)
{
if(strcmpi(cna,p1.na)==0)
{ pos=ifile.tellg();
p1.showdata();
cout<<"\n \t\t ARE YOU SURE TO DISCHARGE THIS PATIENT(y/n)? \n \t\t";
ch=getche();
getch();k=1;
break;
} }
}
if(k!=1)
{ cout<<"\n NO SUCH RECORD PRESENT\n";
getch();
ifile.close();
goto xy;}
ifile.close();
if(ch=='y'||ch=='Y')
{
ifile.open("file1.dat");
while(!ifile.eof())
{
ifile.read((char*)&p1,sizeof(p1));
if(pos!=ifile.tellg())
temp.write((char*)&p1,sizeof(p1));
}
ifile.close();
temp.close();
remove("file1.dat");
rename("temp1.dat","file1.dat");
} }
break;
case '5':
break;
case '6':
char id[5];
clrscr();
cout<<"\n ENTER THE ADMIN ID\t\t---- ";
gets(id);
if(strcmp(id,"70176")==0)
{
cout<<"\n\n\n\t\t\t VERIFICATION SUCCESSFUL ";
getch();
if(!ifile)
{cout<<"unable to open file";
getch();}
else
{
ifile.clear();
ifile.seekg(0,ios::beg);
while(!ifile.eof())
{ ifile.read((char*)&p,sizeof(p));
p.showdata();
getch();
}
} ifile.close(); }else
{ cout<<"\n\n\t\t\t!!!!!! FAILED TO VERIFY!!!!!!\n"; getch();}
break;
default :
cout<<"\n ERROR \n";
cout<<"\a";
getch();
break;}}
while(ch!='5');
}
if the code is not clear here is the link to download it https://drive.google.com/file/d/1hTz3awCDaW-40ewEbpK1VHYa6k5SoD-d/view?usp=sharing