Text File database

Ok, I wanted to make a pretty basic program to make a database, using text files.

I have finished it now, it will compile, etc, but when you enter the details of some person, somehow, no text file is created. :confused:
Maybe one of you can see what I'm doing wrong:

[Edit]

I cut out the *Wrong* code, you can see the (Semi)final thing below.

I attatched the old code in a text file, might you want to see.

[/Edit]

Quote:

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I have finished it now

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:p :p :p

The filename contains illegal characters. use stringstream to convert the employee number into a string, something like this:

Code:

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                cout<< "Id Number?\n:"; // Seems pretty self-explanatory to me.
                cin>> employee.id_no;
                stringstream s;
                s << employee.id_no;
                s >> _id;

---

just to expand a little more on what Ancient Dragon said,,,

the reason you are getting illegal characters in the file name is because when you say...

Code:

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string half_filename = _id + txt;

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you are getting the ascii char value of _id instead of the actual int value you want..

so if the id is 44 then when the file is created it is Member,.txt and if id is 33 then you get Member!.txt .. get it..?

otherwise it is working.. well the entry creation is.. i ran it on linux and it runs with no problems.. creates the files and info in them..

good luck.

Thanks a lot for all your help, I'll rewrite it now :D

I get an error, about stringstream:

Quote:

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40 C:\Dev-Cpp\DatabaseProject.cpp aggregate `std::stringstream s' has incomplete type and cannot be defined

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How does stringstream work? Just curious :)

to Xhi: But even so, shouldn't it still make a *.txt file? On this ( Win 2000 ) Machine, it won't make anything, no text file, nothing

you need
#include <sstream>

and a summary of how i would use a stream here is like..

Code:

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int id=0;
stringstream sstr;
string filename="";

cin >> id;
sstr << id;
filename = sstr.str() + ".txt";

---

>> to Xhi: But even so, shouldn't it still make a *.txt file? On this ( Win 2000 ) Machine, it won't make anything, no text file, nothing

i forgot in my last post.. i wanted to tack on that if you want to test your current code you should be able to enter an id between 48 and 57 and it should work..

Thanks a lot, my file creation is working now, I will adapt the file reader in a moment.

The reason I'm saving the choice via a detour ( first into a struct, and then converting ) is because when I started making this, I had just learned about structures, and wanted to do something with them. It just happend to get a little bigger then expected :P

Would it work if I attatched a string like c:/Dev-cpp/database/ to my filename, and would that store it in a subdirectory?

>> Would it work if I attatched a string like c:/Dev-cpp/database/ to my filename, and would that store it in a subdirectory?

IMO, its not a good idea to put the entire path in the string.. but you can just put the subdir in there..

so instead of prepending

Code:

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c:\Dev-cpp\database\

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just prepend

Code:

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database\

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then it is flexible, so if you want to run the executable from My Documents it will create a subdir under My Documents called databse.. see?

also.. which way are your slashes going in that exmaple.. looks like you normally are on *nix?? ;)

lol :)

I work with both, and I prefer Linux ( Fedora Core ), right now I am at my grandmothers house, so I'm using a diffrent PC then normal, at home I just reformatted my PC, but I'll put in a Win XP / Linux dualboot soon :)

Thanks for your time, you've been a great help to me.

[Edit]

Besides, is a forward slash not the safest thing to use in C++ anyway?
;)

[/Edit]

[Edit]

Thanks again !!!!

[/Edit]

[Edit]

Again, to avoid heaps of code, I will post the .txt file with the 'Classic' Database thingy.

yesss. i see i recieved a special mention.. im speechless.. good thing i have somthing prepared..

Code:

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oh my, i have been dreaming of this day for so long..
i have so many people to thank. my parents.. my manager ..
all of my friends on the west side,
you stuck with me through thick and thin and...

---

my well never mindd.. ;) enough of that..

as for the code.. so far so good.. ill leave the nitpicking to you, now that its working you can optomize :)

one little thing though.. be sure to
#include <string>
to avoid any problems when moving between compilers..

good luck..

Thanks again for the great help.

Nice speech!! :P

I was thinking of expanding it, not sure what to add though :)

I have stumbled across another problem:

When I try to run

[Edit]
Changed, new code down below.
[/Edit]

This, and, when running, select option 2 ( Read from file ) and then say that I dont know what number to choose, then it should give me a listing of things in the /database folder, but it doesn't, it just skips right throuh that part, and goes on asking me if I want to quit, without naming the diffrent *.txt files in the folder.

( I know it says it's finished, thats because it was, I just began tweaking it. )

Here's your problem. This is undefined.

Code:

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number = number++;

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->

Code:

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number++;

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Code:

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else if ( answer != 1 ) {

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->

Code:

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else

---

Code:

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                  cin.ignore();
                  cin.get();

---

See the FAQ on how to clear stdin.

Instead of using a 1/4 symbol for end-of-record, you might want to use a NULL character.

BTW, you never close file_list.

Your break in the case 2 isn't in the right place. It's in the second if. If the first if is true, execution will continue into the default case, printing "wtf". Solution: move the break to outside the if.

And BTW, you can split strings to make the listing easier to read, and the preprocessor will join them.

Ok, with your help, I made it work, only not as it should.

It does show file names, but it doesn't increment the file number with 1 ( Member1.txt -> Member2.txt , etc. )

I might be doing something wrong with the if statement, but I cant really c what.

Code:

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Removed, no longer neccesary.

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(( I only put in the 2nd case, otherwise it might be a bit long ))

Also, why should I want to clear stdin?

Thanks for all your help so far :)

couple of things..

you seem to have doubled everything in the do.while...
incrementing number twice, and opening the file twice (while only closing once)..
and i dont think the way you are using sstream will work.. and to do this you will have to clear the sstream every iteration.. so somthing like this maybe inside the do.while..

Code:

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convert.str("");
convert << number;
number_string = convert.str();
filename = name + number_string + txt;
file_list.open(filename.c_str());
if(file_list.is_open()){
    cout << filename << "\n";
    file_list.close();
}

---

one thing i would do is to create a db file that keeps track of all of these entries.. so you dont have problems when you skip an id number or when you delete members..

so the db file would contain stuff like ..
the total # of Members -- so you know when you can stop scannign for members
all the member ids.. so you can read a member out of the db file and then go open up the member data file.. then if there is a problem opening the data file report it as an error..

just a thought..

oops

>> It does show file names, but it doesn't increment the file number with 1 ( Member1.txt -> Member2.txt , etc. )

the reason it did not seem to be incrementing was because of the way you were using the sstream..

this is from the top of your program where it works

Code:

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sstr << id;
string filename = name + sstr.str() + txt;

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this is from the bottom where it does not ..

Code:

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number++;
convert << number;
convert >> number_string;
filename = name + number_string + txt;

---

could (should) have been

Code:

---

number++;
convert << number;
filename = name + convert.str() + txt;

---

see the difference.. you threw in an extra string which didnt hurt, but then stopped using sstr.str() which you do need.

i wnated to throw this in the other one but forgot..

Ok, I hadn't seen your post, so I began tweaking this myself.

[Edit]

I put code here earlier on, but I'm gonnan rewrite the program for a Db.txt file anyway, so I'll just skip the new search thing, and replace it with the DB file.

Great idea, thanks :) :D :cool:

Lol, I see what you are saying, I had absolutely no idea of that :)

[/Edit]

*snip*

Your Db idea is great, I'll think about how to add that.

Ideas:

Code:

---

/*
  30-12-05 20:38
  Thanks people of the cboard forum!!!
  Special thanks:
          xhi
          xhi
          xhi
          xhi
          *Repeat 200000 times*
          Me
*/
/*
  Ideas to implement:
        DB.txt file, which includes:
              Errors
              Member names + id's ( So the search routine can be skipped altogether. )
*/

---

>> here are still a few minor problems, but thats just because if I work too long on a project, it becomes harder to see the code.

i know that feeling.. many a project has been screwed up at 4am.. :)

just be careful you dont get lost.. looked like on that last bit of code you posted that you were starting to get a little off track.. ? its a simple solution.. so if you are approaching 20 lines of code in that do.while.. you should step back for a minute(s).. check out that snippet i posted two posts ago.. :) it will help..

btw.. it is working except for that little bit in the do.while.. i altered it and the program works.. it reads all the member files until it comes to a break.. i had 4 member files created, 1 2 3 and 12.. it read 1,2,3 just fine.. so you are on the right path still.. just dont go wandering off of it.. :)

Thanks :)

Although I think I will do It like this:

• A DB_Mem.txt file with the memebers ( Name and Id ).
• A DB_err.txt file with any error messages taht might be generated.

Done:

Code:

---

                clrscr();
                cout<< "Id Number?\n:"; // Seems pretty self-explanatory to me.
                cin>> employee.id_no;
                stringstream s;
                s << employee.id_no;
                s >> iid;
                clrscr();
                cin.ignore();
                cout<< "Full Name?\n:";
                getline(cin, employee.name, '\n');
                clrscr();
                cout<< "Age?\n:";
                cin>> employee.age;
                clrscr();
                string full_filename = name + iid + txt;
                ofstream write_file ( full_filename.c_str() ); // Below, all of the input is printed into a text file.
                write_file<< "Name:\n"<< employee.name << "\n\n" << "Age:\n" << employee.age<< "\n\n" << "Id Number:\n" << employee.id_no << "\n\n¼";
                write_file.close();
                ofstream write_db_file ( "database/DB_Mem.txt" ); // <-- I didn't make this up.. You know who did ;)
                write_db_file<< employee.name << "  Id: " << employee.id_no << "\n"; // Makes a DB_Mem.txt file in the database subdir.
                clrscr();                                                            // Will Make the search func MUCH easier to write :)
                break;                                                                // Thumbs up for me not being off track ;)
                }

---

I'll do the member lookup thing right away.

This might be getting a bit ahead of yourself, but most databases rely on some sort of encryption to protect their contents.

Think about it like this. A company uses a database. All the information about their employees are on this database, contained within text files.

Everyone can read the text files so in effect, their contents are public. Employee A can read information about Employee B and vice versa- Problem.

The question is how to you make it so that employees can only access information personal to them, yet at the same time allow all employees to use the SAME database?

Answer, encryption.

Check out XOR encryption... It's reasonbly simple... Good luck.

Hey....

You got a point there :)

I'll try, but I'm only at:
Recursion--a function calling itself

Of the Tutorial....

Bah, who cares, I'll try to finish what I need for encryption, and see how far I get :)

Thank you for all the great ideas, for a small side project to see what I have learned, this has already become quite big :D

*Grins a very happy grin*

Ok, I'm not really filled in on the XOR encryption yet, I'll come to that.

This is the program, with filly implemented search & DB_Mem.txt. :D

@Xhi This also gets around the prob of Id's 1,2,3 and then 12, since it just reads whatever is inside the text file :)

Code:

---

#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <clrscr.h> // Yesyes, a custom header thingy, but no credit 2 me, it's taken from the faq.

using namespace std;
/*
  30-12-05 20:38
  Thanks people of the cboard forum!!!
  Special thanks:
          xhi
          xhi
          xhi
          xhi
          *Repeat 200000 times*
          Me
*/
/*
  Ideas to implement:
        DB.txt file, which includes:
              Errors
              Member names + id's ( So the search routine can be skipped altogether. )
*/
struct dbase_read {
      int id_no;
      string name;
      int age;
      };

int main() {
    int x = 0;
    dbase_read employee; // This program creates a text file for each new entry,
                        // in a subfolder called database.
                        // hey, maybe I'll add a mobile phone/ house phone number function!!! :D
    while ( x != 1 ) { /*See the explanation ( At the bottom )*/
    cout<< "Do you want to:\n\n1. Create a new employee\n2. Read the Database\n\n:";
    int choice;
    cin>> choice;
    string txt = ".txt";
    string name = "database/Member";
    string iid;
    switch ( choice ) {
          case 1: {
                clrscr();
                cout<< "Id Number?\n:"; // Seems pretty self-explanatory to me.
                cin>> employee.id_no;
                stringstream s;
                s << employee.id_no;
                s >> iid;
                clrscr();
                cin.ignore();
                cout<< "Full Name?\n:";
                getline(cin, employee.name, '\n');
                clrscr();
                cout<< "Age?\n:";
                cin>> employee.age;
                clrscr();
                string full_filename = name + iid + txt;
                ofstream write_file ( full_filename.c_str() ); // Below, all of the input is printed into a text file.
                write_file<< "Name:\n"<< employee.name << "\n\n" << "Age:\n" << employee.age<< "\n\n" << "Id Number:\n" << employee.id_no << "\n\n¼";
                write_file.close();
                ofstream write_db_file ( "database/DB_Mem.txt", ios::app ); // <-- I didn't make this up.. You know who did ;)
                write_db_file<< employee.name << "  Id: " << employee.id_no << "\n"; // Makes a DB_Mem.txt file in the database subdir.
                clrscr();                                                            // Will Make the search func MUCH easier to write :)
                break;                                                                // Thumbs up for me not being off track ;)
                }
          case 2: {
                int know_id;
                cout<< "Do you know the persons Id?\n:";
                cin.ignore();
                cin>> know_id;
                cin.ignore();
                clrscr();
                if ( know_id == 1 ) {
                  cout<< "What is the Id Number of the person you want the details of?\n\nEnter Id:";
                  int id=0;
                  cin>> id;
                  stringstream sstr;
                  sstr << id;
                  string read;
                  string filename = name + sstr.str() + txt;
                  ifstream read_file ( filename.c_str() );
                  getline(read_file, read, '¼');
                  clrscr();
                  cout<< read;
                  cin.ignore();
                  cin.get();
                  clrscr();
                  }
                else {
                  ifstream db_mem ( "database/DB_Mem.txt" );
                  string db_read;
                  getline(db_mem, db_read, '\0');
                  cout<< "These are the members:\n" <<  db_read;
                  cin.get();
                  }
                break;
                }
          default: {
                cout<< "Wtf?"; // Best I could think of ;)
                break;
                }
          }
    clrscr();     
    cout<< "Quit?\n:"; // So you don't have to restart the program when you want to do something again.
    cin>> x; // See the while loop, if x does not equal 1, then it continues.
    clrscr();
    }
clrscr();
cin.get();
}

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Ok, I have read the XOR encryption thing, and I think I understand the principle, but the example on that page is a little vague to me, doe anyone happen to have a clear example ( Perhaps something with comment ) so I can see how I can make XOR encryption code?

Also, I would be very happy if that example used C++ Strings instead of C-style strings, because I have used C++ style strings throughout my program.

TIA, you have already been a great help, I wouldn't have been able to do it without you.

Also, I've noticed that if I re-make the same person twice, he/she exists twice in the DB_Mem.txt file, this is because I append all data that the program writes, but actually, I'd like to make a check to see whether or nor a person is already in the database, but I have no idea where to start...

Bright idea, anyone?

http://www.cprogramming.com/snippets...ount=30&page=0

http://www.cprogramming.com/tutorial/xor.html

There's obviously more on google.

However, I don't know about you but I plan on getting very drunk tonight. So if I were you I'd forget what you're doing and do the same.

:D

rofl, thanks for the excellent advice :D

happy new year everyone!

Ok, so I started working on this again this afternoon, but I cant seem to get it work.

It seems as if it cant create any member files, and I have absolutely NO idea why....

The code I'm using is the exact same I used on the win 2000 machine, and I have the custom header (clrscr.h) installed too..

Code is in the above post ( Date: 12-31-2005, 06:21 PM )

TIA

Are you using the same compiler?