fstream - cannot read file

[dunkindonald]

so my code cannot read my file even though i had created a record. when i search for the record, it says record does not exist. here's the code. The part where im getting problem at is on the function void search(int n)

 #include <iostream>
#include <string>
#include <fstream>
#include <iomanip>
#include<stdio.h>
#include<conio.h>
#include <windows.h>

using namespace std;

class student
{
   char Fname[200], MI[5], Lname[200], byear[4], bmonth[2], bdate[2];
   char natio[100], address[100], religion[100], prog[10];
   char hobbies[200], likes[200], disl[200], why[200], dlikes[200], num[20];
   int age, studnum, number, num1, num2;
   static bool yearEntered;
   static bool monthEntered;
   static bool dateEntered;
   
   public:
          void getdata();
          void showdata();
          int retstudnum();            
};

bool student:: yearEntered = false;
bool student:: monthEntered = false;
bool student:: dateEntered = false;

void student::getdata()
{
   cout<<setw(70)<<"Applicant's Registration Form";
   cout<<"\n\nFirst name: ";
   cin.ignore();
   cin.getline(Fname, 100);
   cout<<"\nMiddle Initial: ";
   cin>>MI;
   cout<<"\nSurname: ";
   cin.ignore();
   cin.getline(Lname, 100);
   cout<<"\nAge: ";
   cin>>age;
   cin.ignore();
      do{
	cout<<"\nBirth Year: ";
	cin>>byear;
	string s = byear;
	number = atoi(s.c_str());
	if ( number == 0 )
	cout << "Letter is not alowed :) ";	
	else	
		yearEntered = true;  
	}while(!yearEntered);	
	   do{
	cout<<"\nEnter Birth Month (ex. 01): ";
	cin>>bmonth;
	string s = bmonth;
	num1 = atoi(s.c_str());
	if ( num1 == 0 )
	cout << "Letter is not alowed :) ";	
	else	
		monthEntered = true;  
	}while(!monthEntered);	
	   do{
	cout<<"\nEnter Birth day: ";
	cin>>bdate;
	string s = bdate;
	num2 = atoi(s.c_str());
	if ( num2 == 0 )
	cout << "Letter is not alowed :) ";	
	else	
		dateEntered = true;  
	}while(!dateEntered);	
    cin.ignore();	
   cout<<"\n\nAddress: ";
   cin.getline(address, 100);
   cout<<"\nReligion: ";
   cin>>religion; 
   cout<<"\nMobile Number: ";
   cin.ignore();
   cin.getline(num, 20);
   cout<<"\nProgram/Year: ";
   cin>>prog;
   cout<<"\nStudent number: ";
   cin>>studnum;

   cout<<"\nLikes: ";
   cin.ignore();
   cin.getline(likes, 100);
   cout<<"\nDislikes: ";
   cin.getline(dlikes, 100);
   cout<<"\nWhy JPCS?: ";
   cin.getline(why, 100);
}

void student::showdata()
{
   cout<<"\n\nFirst name: "<<"\t"<<Fname;
   cout<<"\nMiddle Initial: "<<MI;  
   cout<<"\nSurname: "<<"\t"<<Lname;   
   cout<<"\nAge: "<<"\t\t"<<age;   
   cout<<"\nBirthday: "<<"\t"<<bmonth<<" - "<<bdate<<" - "<<byear;   
   cout<<"\nAddress: "<<"\t"<<address;   
   cout<<"\nReligion: "<<"\t"<<religion;    
   cout<<"\nMobile Number: "<<"\t"<<num;  
   cout<<"\nProgram/Year: "<<"\t"<<prog; 
   cout<<"\nStudent number: "<<studnum;   
   cout<<"\nLikes: "<<"\t\t"<<likes;   
   cout<<"\nDislikes: "<<"\t"<<disl;  
   cout<<"\nWhy JPCS?: "<<"\t"<<why;
}

int student::retstudnum()
{
	return studnum;
}

//-------------------------- 
//function declarations     
//---------------------------

void register_form();
void search(int);
//----------------------------
// MAIN FUNCTION
//----------------------------

int main()
{
    char choice;
    int n;
    
    do
    {
        system("cls");
		cout<<setw(50)<<"Junior Philippines Computer Society";
		cout<<setw(60)<<"\n\nMAIN MENU";
		cout<<"\n\n\t01. Register as an applicant";
		cout<<"\n\n\t02. Search for applicants";
		cout<<"\n\n\t03. EXIT";
		cout<<"\n\n\tPlease Select Your Option (1-3) ";
		cin>>choice;
		system("cls");
		switch(choice)
		{
			case '1': register_form();
  	                  break;
			case '2': cout<<"\n\n\tPlease enter student number: ";
                      cin>>n;
                      search(n);
				      break;
			case '3':
				      break;
			default :cout<<"\a";
		}
    	}while(choice!='3');
 

    system("pause<0");
    return 0;
}

void register_form()
{   
	student st;
	ofstream outFile;
	outFile.open("applis.dat",ios::binary|ios::app);
	st.getdata();
	outFile.write((char *) &st, sizeof(student));
	outFile.close();
    	cout<<"\n\nStudent record Has Been Created ";
	cin.ignore();
	getch();
}

void search(int n)
{    
	student st;
	ifstream inFile;
	inFile.open("applis.dat",ios::binary);
	if(!inFile)
	{
		cout<<"File could not be open !! Press any Key...";
		getch();
		return;
	}

	int flag=0;
	while(inFile.read((char *) &st, sizeof(student)))
	{
		if(st.retstudnum()==n)
		{
			 st.showdata();
			 flag=1;
		}
	}
	inFile.close();
	if(flag==0)
		cout<<"\n\nrecord not exist";
	getch();
}
 

[j3Rz8vqX]

Try again.

I've just tested your program, and it works.
After creating an applicant, it saved the data to the root of the projects location. I was able to access the file after that using your list command, and entering the students id.

As a reminder, you program is expecting a distinct data type when reading form file. It is expecting an object read.

Example of working program:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

//Your code...

Please enter student number: 12345 First name: Bob Middle Initial: - Surname: - Age: 43 Birthday: 1215 - 15 - 19701215 Address: - Religion: - Mobile Number: - Program/Year: - Student number: 12345 Likes: - Dislikes: Why JPCS?: -

Edit:

Birthday: 1215 - 15 - 19701215

The projection of birth date, seems a bit off somehow...
I double "tested" it and it still produced answers of that pattern.
-
Update #1: some members were lost after input of new members.

Update #2: //Removed

Update #3:
I am no longer able to produce the errors, from #1, after flushing the data file; DOB bug still persists.

Update #4: Use cin.getline() for input from DOB; you're reading an array of characters. You did so before with First name and such. I believe this caused data members to have become dis-aligned during writing and reading from file.

[Chervil]

I tried this program, (though I trimmed some of the input to save typing lots of optional stuff (including middle initial which may not always be present).

It worked except on one occasion when I had the output file open in another application. That identified a flaw, there's no error checking when writing to the file. I added this code to function register_form():

    if (outFile)
        cout<<"\n\nStudent record Has Been Created ";
    else
        cout << "\n\n Error saving to file"; 

Also, since it isn't easy to browse the file to see what's there, I added a diagnostic option:

void listStudents()
{
    student st;
    ifstream inFile(filename, ios::binary);
    if(!inFile)
    {
        cout<<"File could not be open !! Press any Key...";
        getch();
        return;
    }

    while(inFile.read((char *) &st, sizeof(student)))
    {
        cout << setw(10) << st.retstudnum()
             << setw(30) << st.getfirst()
             << setw(30) << st.getlast()
             << endl;
    }

    cout<<" == end of list ==" << endl;
    getch();

}

as well as within class student

       std::string getfirst() const { return Fname; };
       std::string getlast()  const { return Lname; };

and adding option 4 to the menu to call the new function listStudents().

That was not meant to be particularly good style, just a quick way to view the file.

Note, ifstream inFile(filename, ios::binary); here i declared filename as a constant string to avoid the possibility of different filenames being used throughout the program.