data written in file only in alternate steps - c++

Question

code
#include<iostream>
#include<fstream>
#include<conio.h>
#include<string>
using namespace std;
class student
{
int admno;
char name[20];
// char address[20];
//string name;
public:
void getdata()
{
cout<<"\n\nEnter The Name of The Student ";
//gets(name);
//cin.ignore();
cin>>name;
cout<<"\nEnter The admission no. ";
cin>>admno;
// getch();
}
void showdata()
{
cout<<"\nAdmission no. : "<<admno;
cout<<"\nStudent Name : "<<name<<endl;
//puts(name);
}
void display()
{
//student obj;
ifstream fp1;
fp1.open("student.dat",ios::binary);
while(fp1.read((char*)this,sizeof(*this)))
{
this->showdata();
fp1.read((char*)this,sizeof(*this));
}
fp1.close();
}
void add()
{
ofstream fp2;
fp2.open("student.dat",ios::binary|ios::app);
this->getdata();
fp2.write((char*)this,sizeof(*this));
fp2.close();
}
};
int main()
{
student obj;
//system("cls");
cout<<"\n1. Add new student";
cout<<"\n2. View all student";
cout<<"\n3. Search student";
cout<<"\n4. modify student";
cout<<"\n5. delete student";
cout<<"\n6. Exit";
cout<<"\n\nEnter your choice";
int ch;
cin>>ch;
switch(ch)
{
case 1:
obj.add();
break;
case 2:
obj.display();
//b.viewbook();
break;
default:
cout<<"Enter Valid choice";
}
return 0;
}
problem:
when I enter the data in file, the data is written to the file only in the alternate steps.
at the first run and enter the data it is OK and in second run to add the student, the data isnot written in the file and again in the next step it writes properly and it continues to give proper output in alternate addition.

Answer 1

You should put your switch inside a loop:
bool exitLoop = false;
while(!exitLoop) {
int ch;
cin>>ch;
switch(ch) {
case '1':
obj.add();
break;
case '2':
obj.display();
//b.viewbook();
break;
case '6':
exitLoop = true;
break;
default:
cout<<"Enter Valid choice";
}
}
Also note how to handle character inputs: 1 != '1'