C / C++ / MFC

Re: How to get access to CMyView variables from CMainFrame in MFC

1-Jan-21 4:52

Dear Friend
I did it,Because it seemed very easy, but then I get CDocument ERROR!
After adding #include "CMyView.h" into CMyMainFrame, I get CDocument ERROR!
I searched a lot on the internet, all say use GetActiveView() but it does not work!

Best Regards

Richard MacCutchan1-Jan-21 4:55

Re: How to get access to CMyView variables from CMainFrame in MFC

1-Jan-21 4:55

Sorry, we cannot guess what you are doing. You need to show the code that that you are running, and explain exactly what error(s) you see and where it happens.

Member 150337041-Jan-21 5:06

Re: How to get access to CMyView variables from CMainFrame in MFC

1-Jan-21 5:06

Dear friend
I write the following code inside MyCMainFrame.cpp file :

MyCView*pView = static_cast<mycview*> (GetActiveWindow());
pView->m_CMyView_Pulic_Variable;

To get access to public variables inside CMyview class.

But when I include MyCView.h file inside MyCMainFrame file to use GetActiveView(), then I get CDocument ERROR!

In fact, I just want to change a public variable inside CMyView class from MyCMainFrame.
How can I get access to CMyView class public variables, from MyCMainFrame?

Best Regards

Richard MacCutchan1-Jan-21 5:13

Re: How to get access to CMyView variables from CMainFrame in MFC

1-Jan-21 5:13

Why are you using GetActiveWindow rather than GetActiveView? And what is the exact text of the error you receive and where does it occur?

Member 150337044-Jan-21 7:07

Re: How to get access to CMyView variables from CMainFrame in MFC

4-Jan-21 7:07

Dear Richard
Firstly "HAPPY NEW YEAR"

Many thanks for your help, I was engaged with the CMyDoc error, finally I found it, simply it was redefinition of CMyDoc header in 2 different classes that I never guessed such mistake.

Best Regards

Richard MacCutchan4-Jan-21 9:46

Re: How to get access to CMyView variables from CMainFrame in MFC

4-Jan-21 9:46

Glad you found it. Happy New Year (as much as it can be) to you also.

11917640 Member 4-Jan-21 22:29

11917640 Member

4-Jan-21 22:29

For future use:

MFC Doc/View: How to obtain a pointer to various objects?[^]

Re: How to get access to CMyView variables from CMainFrame in MFC

Member 150337045-Jan-21 2:44

having problem to find an error

5-Jan-21 2:44

Excellent, Thanks

bot-joy28-Dec-20 7:25

bot-joy

28-Dec-20 7:25

Nobita and String | Basics of String Manipulation & Algorithms Practice Problems | HackerEarth[^]

this is the question. my code:

#include<bits/stdc++.h>
using namespace std;

int main()
{
	int t;
	cin>>t;
    std::string s[t];
	for(int i=0;i<=t-1;i++)
	{
   string st;
    getline(cin,st);     
     int l=(int)st.length();
    string s2="",s3="";      
   for(int i=0;i<=l;i++)
   {
       if(st[i]==' '||st[i]=='\0')
       {
           s3=s2+" "+s3;
           s2.clear();
       }
       else
       {
           s2+=st[i];
       }   
   }      
    s[i]=s3;
	}
    for(int i=0;i<=t-1;i++)
    cout<<s[i]<<endl;
    return 0;
}

the error message is saying " your program doesnt print anything. can anyone help me find whats wrong?

jeron128-Dec-20 7:40

jeron1

28-Dec-20 7:40

for(int i=0;i<=l;i++)

Try changing to

for(int i=0;i<l;i++)

You're index is going out of bounds on the st variable 'st[i]', when i is equal to l.
Also, having nested for loops with the same index variable name is tough to read.

"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment
"Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst
"I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle

CPallini28-Dec-20 20:22

CPallini

28-Dec-20 20:22

After the following line

C++

cin>>t;

there are still charactes in the input buffer, hence, the next call to getline gets them.
A commont way to deal with this issue is using cin.ignore (see, for instance What is the use of cin.ignore() in C++?[^]).

"In testa che avete, Signor di Ceprano?"
-- Rigoletto

David Crow29-Dec-20 3:14

David Crow

29-Dec-20 3:14

Have you tried stepping through the code using a debugger? Doing so will let you know in a hurry what is wrong.

"One man's wage rise is another man's price increase." - Harold Wilson

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles

gdi+ bitmap save on existing file - showing error

Patrice T30-Dec-20 12:42

Patrice T

30-Dec-20 12:42

In addition to other answers.

Advice: Learn to indent properly your code, it show its structure and it helps reading and understanding. It also helps spotting structures mistakes.

C++

#include<bits/stdc++.h>
using namespace std;

int main()
{
	int t;
	cin>>t;
	std::string s[t];
	for(int i=0;i<=t-1;i++)
	{
		string st;
		getline(cin,st);
		int l=(int)st.length();
		string s2="",s3="";
		for(int i=0;i<=l;i++)
		{
			if(st[i]==' '||st[i]=='\0')
			{
				s3=s2+" "+s3;
				s2.clear();
			}
			else
			{
				s2+=st[i];
			}
		}
		s[i]=s3;
	}
	for(int i=0;i<=t-1;i++)
		cout<<s[i]<<endl;
	return 0;
}

Indentation style - Wikipedia[^]

Professional programmer's editors have this feature and others ones such as parenthesis matching and syntax highlighting.
Notepad++ Home[^]
ultraedit[^]
Enabling Open Innovation & Collaboration | The Eclipse Foundation[^]

Patrice

“Everything should be made as simple as possible, but no simpler.” Albert Einstein

Gopi Nath24-Dec-20 22:21

Gopi Nath

24-Dec-20 22:21

Hello,

I am trying to draw an image (2nd image) over the other image (existing image file - 1st image) using gdi+ bitmap and graphics and then saving (overwriting) the same 1st image file. But saving is not getting done, when i use GetLasError(), it shows error message,
"The process cannot access the file because it is being used by another process"

Here is the code what i am doing.

C++

<pre>Gdiplus::Bitmap *gpBitmap = new Gdiplus::Bitmap(mImagePath1); /// existing image file
Gdiplus::Graphics *gr = Gdiplus::Graphics::FromImage(gpBitmap);

Gdiplus::Bitmap img(mImagePath2); // second image 
Gdiplus::Bitmap* pThumbnail = static_cast<Gdiplus::Bitmap*>(img.GetThumbnailImage(32, 32, NULL, NULL));
gr->DrawImage(pThumbnail, newWpos, newHpos); // drawing the second image on some position of first image

Gdiplus::Status stat = gpBitmap->Save(mImagePath1, pClsid); // pClsid - image encoder set for png output

I tried making copy also, but same issue.

please suggest.

Regards,
Gopi.

Re: gdi+ bitmap save on existing file - showing error

Richard MacCutchan24-Dec-20 23:33

Solved - gdi+ bitmap save on existing file - showing error

24-Dec-20 23:33

Your file mImagePath1 is still open to the Bitmap object. You should use a different path to save the new image.

Gopi Nath24-Dec-20 23:53

Gopi Nath

24-Dec-20 23:53

Thank you Richard.

This helps me to solve my issue.

Regards,
Gopi.

std:strstream does not work

Haakon S.22-Dec-20 2:38

Haakon S.

22-Dec-20 2:38

In Visual C++ 2012 I have written this code:

strstream& operator>>(strstream& Stream,CComponent* pCmp){
..code
}

std::strstream read_file((char*)filbuf,file_size,ios_base::out);

pComp=new CComponent;
read_file>>pComp;

This works perfectly. But when I run it on my newly installed Visual C++ 2019 it compiles all right, but the output is wrong.

I see that std::strstream is deprecated, but it should still function. If I try to put std::stringstream instead, it will not accept the >> operator.

Richard MacCutchan22-Dec-20 4:14

22-Dec-20 4:14

Haakon S. wrote:
it compiles all right, but the output is wrong.

You need to explain what that means.

Haakon S.22-Dec-20 22:21

Haakon S.

22-Dec-20 22:21

Ok, some details. Everything seems to be identical when I check the debug data. The text file is referenced in the same way by filebuf.

The first member of CComponent is specified as WORD m_nNo and the this value in the first component is 56.

I put some test code on top of my function to try to find out what is going on.

std::strstream& operator>>(std::strstream& Stream,CComponent* pCmp){
	char txt[4];
	Stream >> txt;
.
.
.
}

The watch window displays the following output from the new C++ version:

- txt 0x00cfd5fc "" char[4]
[0] 0 '\0' char
[1] -52 'Ì' char
[2] -52 'Ì' char
[3] -52 'Ì' char

From my older version I get the correct output:

- txt 0x0055e25c "56" char[4]
[0] 53'5' char
[1] 54'6' char
[2] 0 '\0' char
[3] -52 'Ì' char

It seems that the extraction operator >> simply does not work anymore. In that case, what is the best alternative for reading data from a text file. If I replace strstream with stringstream I get the message that stringstream does not have a >> operator.

modified 23-Dec-20 4:35am.

Richard MacCutchan22-Dec-20 23:37

22-Dec-20 23:37

If you are reading from a file then you should be using one of the fstream classes.

Stefan_Lang23-Dec-20 23:59

Stefan_Lang

23-Dec-20 23:59

Looks to me like it is the *old* version that wasn't working: your code overwrites your text variable, so why would you expect it to still hold the old value? Or maybe it is just that the VS2012 debugger didn't show these contents properly because it didn't recognize that you were writing to it.

GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)

Stefan_Lang23-Dec-20 23:56

Stefan_Lang

23-Dec-20 23:56

First, stringstream is not strstream. You may need to specifically use ostringstream instead. But anyway, like Richard already stated, you should be using fstream, or ofstream.

Haakon S.24-Dec-20 0:37

Haakon S.

24-Dec-20 0:37

Hi.

Thanks for helping.

ifstream accepts the >> operator and get() function.

std::ifstream read_file((char*)filbuf,file_size,ios_base::out);
.
.
 pComp=new CComponent;
 read_file>>pComp;

This function is called:

ifstream& operator>>(ifstream& Stream,CComponent* pCmp){

Stream>>pCmp->m_nNo;
Stream.get(pCmp->m_formula,15);
.
.
}

Everything works fine, except that nothing is actually read.

Regards, Haakon.

Richard MacCutchan24-Dec-20 4:18