Re: Why doesn't this work? Simple file I/O - C / C++ / MFC Discussion Boards

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Re: How to write to DataBase MS Access

led mike26-Jul-06 8:41

led mike

26-Jul-06 8:41

DavidCrow wrote:
Have you looked

Rhetorical question? Smile | :)

Why doesn't this work? Simple file I/O

liuphil126-Jul-06 7:25

liuphil1

26-Jul-06 7:25

I got this from a computer science class and it's supposed to create a file for me. I copied it directly, and it doesn't seem to work as nothing shows up in the file. What's wrong? Thanks

#include <fstream.h>
#include<iostream.h>

struct rec
{
char name[25];
int age;
float wt;
};
int main()
{
rec stdrec[8] = {{"helen", 10, 10}, {"julie", 20,20}, {"lena",30,30},{"alan", 40, 40}, {"annie", 50,50},
{"may", 60, 60}, {"lee", 70, 70}, {"ed", 80,80}};

fstream fout("final.dat", ios::out||ios::binary);
int i;

for(i=0; i<8; i++)
{
fout.write((char*)&stdrec[i], sizeof(stdrec[i]));
cout<

Re: Why doesn't this work? Simple file I/O

Zac Howland26-Jul-06 7:47

Zac Howland

26-Jul-06 7:47

Fixed line in bold:

#include <iostream>
#include <fstream>

using namespace std;

struct rec
{
	char name[25];
	int age;
	float wt;
};

int main()
{
	rec stdrec[8] = {	{"helen", 10, 10}, 
				{"julie", 20, 20}, 
				{"lena", 30, 30},
				{"alan", 40, 40}, 
				{"annie", 50, 50},
				{"may", 60, 60}, 
				{"lee", 70, 70}, 
				{"ed", 80,80}
			};

	fstream fout("final.dat", ios::out | ios::binary);

	for(int i=0; i<8; i++)
	{
		fout.write((char*)&stdrec[i], sizeof(stdrec[i]));
		cout 	<< stdrec[i].name << "\t" 
			<< stdrec[i].age << "\t"
			<< stdrec[i].wt <<endl;
	}
	
	return 0;
}

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Re: Why doesn't this work? Simple file I/O

liuphil126-Jul-06 8:01

liuphil1

26-Jul-06 8:01

Thanks, I tried to run it, but the file output is weird. Is this because it's in binary mode? Sorry I'm still new to programming.

Re: Why doesn't this work? Simple file I/O

David Crow26-Jul-06 8:18

David Crow

26-Jul-06 8:18

liuphil1 wrote:
...the file output is weird.

Define "weird."

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

Re: Why doesn't this work? Simple file I/O

liuphil126-Jul-06 8:52

liuphil1

26-Jul-06 8:52

It's all on one line, and there's a lot of strange characters that were not in the initializations.

Re: Why doesn't this work? Simple file I/O

Zac Howland26-Jul-06 8:57

Zac Howland

26-Jul-06 8:57

Its a binary file. Reading it in Notepad, Wordpad, or any other text editor will show you lots of weird characters.

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Re: Why doesn't this work? Simple file I/O

Zac Howland26-Jul-06 8:56

Zac Howland

26-Jul-06 8:56

You won't be able to read the file. It is in binary. If you want to look at it, open it up in a hex editor to verify its contents. Otherwise, write a method to read in the data in a similar fashion to the way it is written and then print it to the screen:

fstream fin("final.dat", ios::in | ios::binary);
while (!fin.eof())
{
	rec r;
	fin.read((char*)&r, sizeof(rec));
	cout 	<< r.name << "\t" 
		<< r.age << "\t"
		<< r.wt <<endl;
}

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

form Displaying

ningthemcha26-Jul-06 6:46

ningthemcha

26-Jul-06 6:46

i create a dialog based application
it consists of two from class
form1 and form2

i can display form1 like this
CDialog form1(IDD_FORM1)
form1.DoModal();
if i try to display form2 from
form1 by OnOK()method like this
CDialog form2(IDD_FORM2)
form2.DoModal();
IT IS NOT WORKING
HOW CAN I DO IT

janan

Re: form Displaying

C^hris L^osinger26-Jul-06 7:04

C^hris L^osinger

26-Jul-06 7:04

ningthemcha wrote:
IT IS NOT WORKING

what happens ?

can you post the relevant parts of your code ?

Let's execute on the customer-facing market-driven swim-lane paradigm!

Re: form Displaying

David Crow26-Jul-06 7:06

David Crow

26-Jul-06 7:06

See MSDN article Q138681.

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

Re: form Displaying

Zac Howland26-Jul-06 7:28

Zac Howland

26-Jul-06 7:28

I'm guessing that Form1 is your main dialog for your application? That being the case, when you click "OK", it ends up exiting the program. So even if you spawn another dialog, the main thread is exiting.

Use a different button, or don't call CDialog::OnOK in your OnOK handler ... or don't use Form1 for your main dialog.

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Re: form Displaying

Hamid_RT26-Jul-06 7:29

Hamid_RT

26-Jul-06 7:29

Do you get error?if yes what if no whats happen?

WhiteSky

debug assertion failed

identity_8526-Jul-06 5:42

identity_85

26-Jul-06 5:42

i made a program using flexgrid ActiveX control and when i run and call a function from the flexgrid class i got a debug assertion failed mesaage

Re: debug assertion failed

Hamid_RT26-Jul-06 6:05

Hamid_RT

26-Jul-06 6:05

Can you be more specific

WhiteSky

Re: debug assertion failed

Cedric Moonen26-Jul-06 6:05

Cedric Moonen

26-Jul-06 6:05

Use your debugger to see where your program crashes.
And if you want more chances to get an answer you have to provide a lot more informations (but still, use your debugger and if you are stuck, THEN post informations that comes from your debugger).

Cédric Moonen
Software developer

Charting control

Re: debug assertion failed

identity_8526-Jul-06 6:24

identity_85

26-Jul-06 6:24

when calling msflexgrid::clear() for example the program fails in this line
ASSERT(m_pCtrlSite != NULL); in the vs/src/WINOCC.cpp file

Re: debug assertion failed

Zac Howland26-Jul-06 6:35

Zac Howland

26-Jul-06 6:35

Are you calling AfxEnableOleAutomation() or CoInitialize() in your InitInstance function?

Usually you get those types of assertions when you haven't initialized COM.

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Re: debug assertion failed

identity_8526-Jul-06 7:59

identity_85

26-Jul-06 7:59

how can i initialize COM? and what's the declaration for these two functions?

Re: debug assertion failed

David Crow26-Jul-06 8:23

David Crow

26-Jul-06 8:23

identity_85 wrote:
how can i initialize COM?

By using one of the two functions that Zac mentioned.

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

Re: debug assertion failed

Zac Howland26-Jul-06 9:02

Zac Howland

26-Jul-06 9:02

DavidCrow wrote:
identity_85 wrote:
how can i initialize COM?

By using one of the two functions that Zac mentioned.

This is about the time where I would tell him to take his hands off the keyboard, go to Barnes and Noble, buy any Intro to C++ book and any Intro to COM book ... and not to touch the keyboard again until both have been read and understood ... *sigh*

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Re: debug assertion failed

David Crow26-Jul-06 9:10

David Crow

26-Jul-06 9:10

Zac Howland wrote:
This is about the time where I would tell him to...go to Barnes and Noble...

Be sure to include directions.

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

Re: debug assertion failed

identity_8526-Jul-06 9:39

identity_85

26-Jul-06 9:39

program fails cause in ASSERT(m_pCtrlSite != NULL); "m_pCtrlSite" not an OLE control ?? will these two functions solve it and if so what's the directions or classes of them plz?

Re: debug assertion failed

David Crow26-Jul-06 9:54

David Crow

26-Jul-06 9:54

identity_85 wrote:
will these two functions solve it

Very doubtful. Had you failed to initialize COM, the application would have most likely failed to even start.

I created a dialog-based project and added the Microsoft FlexGrid v6 Control to it. I then added the control to the dialog template. At this point, I could compile and run the application fine. What else do you have in place?

"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank

"Judge not by the eye but by the heart." - Native American Proverb

Re: debug assertion failed

Zac Howland26-Jul-06 10:26

Zac Howland

26-Jul-06 10:26

DavidCrow wrote:
Had you failed to initialize COM, the application would have most likely failed to even start.

It would have started, but as soon as any access to the control was made, it would have given an assertion (in debug) or just crashed (in release).

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

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