C / C++ / MFC

how to get difference between two dates using CDateTimeCtrl ?

27-Mar-07 5:54

MachineMHK wrote:
Hi, i want detect any change in desktop area. Like...desktop wallpaper change, etc

Assuming that SystemParametersInfo() was used to make the change, handle the WM_WININICHANGE message.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

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

jalsa G27-Mar-07 4:13

jalsa G

27-Mar-07 4:13

hi all,

how to get difference between two dates using CDateTimeCtrl ?

venu

Re: how to get difference between two dates using CDateTimeCtrl ?

Iain Clarke, Warrior Programmer27-Mar-07 4:48

Iain Clarke, Warrior Programmer

27-Mar-07 4:48

Simple - extract the date / time from the control CDateTimeCtrl::GetTime (...). You would then have a CTime, SYSTEMTIME, or even a COleDataTime.

CTime has comparison functions you can use.

Iain.

Re: how to get difference between two dates using CDateTimeCtrl ?

David Crow27-Mar-07 5:56

Sorting a vector of non-primitive data types (structs)

27-Mar-07 5:56

Put the two times in a COleDateTime object, and get the difference via COleDateTimeSpan.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

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

all_in_flames27-Mar-07 3:08

Re: Sorting a vector of non-primitive data types (structs)

27-Mar-07 3:08

Hi everyone,
I'm attempting to write a program that takes command line arguments, reads data in from a file,
and then appropriately searches for certain data or sorts the data for output based on the argument passed.

I am having trouble figuring out how to actually sort the vectors according to the attributes.
the struct is as follows:

<br />
struct Wizard<br />
{<br />
string FirstName;<br />
string LastName;<br />
int Grade;<br />
double WandWeight;<br />
};<br />

The datafile being read from simply has each property separated by a single whitespace character. The vector is declared simply as:

<br />
vector(Wizard) wizVec;<br />

(NOTE: angle braces would not show up in preview, assume they take the place of the round braces in the vector declaration)

Don't ask about the name of the struct, it's my prof's example!
Any suggestions or solutions are appreciated and needed!
Thanks in advance!

Christian Graus27-Mar-07 3:12

Christian Graus

27-Mar-07 3:12

To get < and > to show, you need to check 'Ignore HTML tags' below.

You can write a function object that compares two Wizard objects, and pass that into the sort algorithm.

Here[^] is an article on the subject.

Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

Re: Sorting a vector of non-primitive data types (structs)

Stephen Hewitt27-Mar-07 4:05

Re: Sorting a vector of non-primitive data types (structs)

27-Mar-07 4:05

Use std::sort to sort the vector. Add an operator < for your struct to define the sort order or code a predicate function or functor and pass it to std::sort.

Steve

all_in_flames27-Mar-07 5:16

Re: Sorting a vector of non-primitive data types (structs)

27-Mar-07 5:16

Thanks for the article Christian, and the suggestion, Stephen. I will try to follow the instructions in the article. I appreciate the help, and the speedy replies Smile | :)

Does this logic make sense in context?

void SortVecAscending(vector<Wizard> &wizVector, string prop)
{
// Sort vector smallest to largest, according to prop(erty)
bool compare_Wizards(const Wizard& a, const Wizard& b)
{
return a.prop < b.prop;
}

std::sort(wizVector.begin(), wizVector.end(), compare_Wizards);
}

Christian Graus27-Mar-07 6:02

Christian Graus

27-Mar-07 6:02

Yes, that looks like it should work.

Re: Sorting a vector of non-primitive data types (structs)

Stephen Hewitt27-Mar-07 13:33

Re: Sorting a vector of non-primitive data types (structs)

27-Mar-07 13:33

C++ does not support local functions (functions in functions). You can have functors in function however.

Steve

Stephen Hewitt27-Mar-07 13:33

Re: Sorting a vector of non-primitive data types (structs)

27-Mar-07 13:33

C++ does not support local functions (functions in functions). You can have functors in function however.

Steve

all_in_flames27-Mar-07 12:12

Re: Sorting a vector of non-primitive data types (structs)

27-Mar-07 12:12

Thanks again for all your help, gentlemen. I got the sorting working with no more problems.
However, now that I have moved on to the searching portion, I find that the way the project is designed,
I have to search for values in the structs that are NOT strings.

To refresh your memory:
struct Wizard
{
string FirstName;
string LastName;
int Grade;
double WandWeight;
};

Is there any viable way to convert a string to an int, a string to a double, or vice versa?
I have attempted to use static_cast<string>() on the int and double values, and static_cast<int>() / static_cast<double>() on the string values, but the compiler didn't like those conversions.

I have looked around, and there is nothing available to me without downloading someone's class and using it. Since this is a school project, I have a feeling that would be frowned upon.

Any ideas?

If any clarification is needed, simply ask.

Stephen Hewitt27-Mar-07 13:47

Re: Sorting a vector of non-primitive data types (structs)

27-Mar-07 13:47

There are multiple ways, here's one:

// CommandLine.cpp : Defines the entry point for the console application.
//
 
#include "StdAfx.h"
#include <iostream>
#include <string>
#include <sstream> // For 'istringstream'.
 
int main()
{
	using namespace std;
 
	string s = "1234";
	int num;
	istringstream ss(s);
	ss >> num;
	if (ss)
	{
		cout << "Number is " << num << endl;
	}
 
	return 0;
}

And another:

// CommandLine.cpp : Defines the entry point for the console application.
//
 
#include "StdAfx.h"
#include <iostream>
#include <string>
#include <cstdlib>
 
int main()
{
	using namespace std;
 
	string s = "1234";
	int num = atoi(s.c_str());
	cout << "Number is " << num << endl;
 
	return 0;
}

The second method is easier but error handling is more difficult as if no valid conversion could be performed, a zero value is returned. Also, in the first version simply changing the type of the num variable will make the code work different types but the second version requires a distinct function for each type: atoi only works for ints.

Steve

all_in_flames27-Mar-07 13:54

Re: Sorting a vector of non-primitive data types (structs)

27-Mar-07 13:54

Thanks again!
I ended up using the stringstream approach, as our prof is fanatical about us not using "pure" C functions.

You guys are life savers!

Regards,

Bryan

Stephen Hewitt27-Mar-07 13:57

Re: Sorting a vector of non-primitive data types (structs)

27-Mar-07 13:57

Your professor is a wise man.

Steve

Michael Dunn27-Mar-07 20:36

Michael Dunn

27-Mar-07 20:36

all_in_flames wrote:
Is there any viable way to convert a string to an int, a string to a double, or vice versa?

For future reference, we have a FAQ here Smile | :)

--
6.3 How can I change a number into its string representation, or vice versa? [^]

--Mike--
Visual C++ MVP Cool | :cool:

LINKS~! Ericahist | PimpFish | CP SearchBar v3.0 | C++ Forum FAQ

Ford, what's this fish doing in my ear?

Re: Sorting a vector of non-primitive data types (structs)

all_in_flames28-Mar-07 2:16

28-Mar-07 2:16

Thanks for the info, Mike!
I'm a codeproject n00b, but I get the newsletter! Wink | ;)

lparam and wparam

Try27-Mar-07 2:59

Try

27-Mar-07 2:59

What are these 'lparam' and 'wparam' ? Where can i get info abt these?

Consider:
BOOL PostMessage(
UINT message,
WPARAM wParam = 0,
LPARAM lParam = 0
);

MSDN says
The content of 'lparam' and 'wparam' parameter depends on the message being posted.
What will be the values when mouse is clicked or key is pressed?

Thanks in Advance.

David Crow27-Mar-07 3:03

27-Mar-07 3:03

LameThought wrote:
What are these 'lparam' and 'wparam' ?

They are message-specific values. Some messages use one, the other, both, or neither.

LameThought wrote:
Where can i get info abt these?

MSDN, CP, Google.

LameThought wrote:
What will be the values when mouse is clicked or key is pressed?

Again, it all depends on the specific message you are inquiring about.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

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

Try27-Mar-07 3:12

Try

27-Mar-07 3:12

Now, i want to Set Focus for Edit Box in Dialog using PostMessage, then what will be the values of both?

David Crow27-Mar-07 3:18

27-Mar-07 3:18

Use the SetFocus() function for this.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

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

Michael Dunn27-Mar-07 20:40

Michael Dunn

27-Mar-07 20:40

In a dialog, use WM_NEXTDLGCTRL which automagically handles the subtleties in how dialogs handle focus. More from Raymond: Clickety[^]

--Mike--
Visual C++ MVP Cool | :cool:

LINKS~! Ericahist | PimpFish | CP SearchBar v3.0 | C++ Forum FAQ

Ford, what's this fish doing in my ear?

prasad_som27-Mar-07 4:00

prasad_som

27-Mar-07 4:00

You should use SetFocus API in this case as David said earlier.
If you see documentation for WM_SETFOCUS, it will tell you, what should be values passed, as wParam and lParam.
It applies to all windows messages.

Prasad
Notifier using ATL | Operator new[],delete[][^]