C / C++ / MFC

Re: Error while using static int for incremental record.

10-Mar-18 1:09

Tarun Jha wrote:
but it's giving error.

And we must guess what that error is, and where it occurs?

Tarun Jha10-Mar-18 1:44

Tarun Jha

10-Mar-18 1:44

this is what compiler is showing:

Quote:
/tmp/ccDcxr5a.o: In function Names::setcode()':
savinglistOfNames.cpp text._ZN5Names7setcodeEv[_ZN5Names7setcodeEv]+0xe): undefined reference toNames::count'
savinglistOfNames.cpp text._ZN5Names7setcodeEv[_ZN5Names7setcodeEv]+0x17): undefined reference to Names::count'
savinglistOfNames.cpp text._ZN5Names7setcodeEv[_ZN5Names7setcodeEv]+0x1d): undefined reference toNames::count'
collect2: error: ld returned 1 exit status

Re: Error while using static int for incremental record.

Richard MacCutchan10-Mar-18 2:04

Re: Error while using static int for incremental record.

10-Mar-18 2:04

You have declared the variable count in your Names class, but never defined it in your code. Add the following line after the class declaration:

int Names::count;

CPallini10-Mar-18 11:27

CPallini

10-Mar-18 11:27

two errors

Member 137186819-Mar-18 21:24

Member 13718681

9-Mar-18 21:24

1>ModifyDlg.obj : error LNK2001: 无法解析的外部符号 "public: virtual int __thiscall CModifyDlg::OnInitDialog(void)" (?OnInitDialog@CModifyDlg@@UAEHXZ)
1>WorkDlg.obj : error LNK2001: 无法解析的外部符号 "protected: virtual int __thiscall CWorkDlg::OnInitDialog(void)" (?OnInitDialog@CWorkDlg@@MAEHXZ)

Re: two errors

Victor Nijegorodov9-Mar-18 21:44

Linker Tools Error LNK2001
How to fix?: error LNK2001: unresolved external symbol "extern "C" ........
error LNK2001 - Google Search

9-Mar-18 21:44

how to get a string as input ?

Tarun Jha9-Mar-18 16:45

Tarun Jha

9-Mar-18 16:45

Here's what i have tried.

#include <iostream>
#include <cstring>
#define MAX 100
using namespace std;

int m=0;
class Names{
        char name[5][30];
        //static int m;
    public:
        //Names(){m++;}
        void getdata(){
            //int temp = m;
            //string s;
            cout<<"Entre name :\t";
            cin.ignore(1000, '\n');
            cin>>name[m];
            //getline(cin, name[m]);
            //strcpy(name[m],s);
            m++;
        }
        void display(void){
            for(int i=0; i<m; i++){
                cout<<name[i]<<endl;
            }
        }
};

int main(){
    Names x;
    for(int i=0; i<5; i++){
        x.getdata();
    }
    x.display();

    return 0;
}

i tried getline(), but it was giving error. How do i take a string as a input ?

modified 10-Mar-18 0:37am.

Re: how to get a string as input ?

Sampath5799-Mar-18 20:15

Re: how to get a string as input ?

9-Mar-18 20:15

Please test it and let me know whether it solved your requirement.

#include <iostream>
#include <string>

#define MAX 100
using namespace std;


class Names {
	string name[3];
	//static int m;
public:
	//Names(){m++;}
	void getdata() 
	{
		for (int i = 0; i < 3; i++)
		{
			cout << "Enter Names:" << endl;
			getline(cin,name[i]);
		}
	}
	void display(void) {
		for (int i = 0; i<3; i++) {
			cout << name[i] << endl;
		}
	}
};

void main()
{
	Names n;
	n.getdata();
	n.display();
	getchar();
}

David Crow10-Mar-18 11:07

David Crow

10-Mar-18 11:07

Tarun Jha wrote:

i tried getline(), but it was giving error.

Can you make your font size larger? I cannot see the error from here.

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Re: how to get a string as input ?

Tarun Jha15-Mar-18 7:50

Tarun Jha

15-Mar-18 7:50

i will try .
and thank you

How can I minimize memory usage in my table-based statemachine with several hundred states?

arnold_w9-Mar-18 9:02

arnold_w

9-Mar-18 9:02

I am working with an ARM microcontroller and I have kind of a statemachine with several hundred states. In order to be able to overview it, I have written the code so that it has a 1:1 correspondence with a flowchart specification. I have removed irrelevant code, but basically the code works like this:

Bool_t (*returnTrueOrFalseFunctionPtr) (void);
void (*actionFunctionPtr) (int);

struct myStruct_s {
    returnTrueOrFalseFunctionPtr   trueOrFalse;
    struct myStruct_s*             whereToGoIfTrue;
    struct myStruct_s*             whereToGoIfFalse;
    actionFunctionPtr              actionsToPerformInThisState[5];
    int                            actionArguments[5];
};

static struct myStruct_s myStateMachine1[];
static struct myStruct_s myStateMachine2[];
static struct myStruct_s myStateMachine3[];
static struct myStruct_s myStateMachine4[];

define myStateMachine1 ms1
define myStateMachine2 ms2
define myStateMachine3 ms3
define myStateMachine4 ms4

static struct myStruct_s myStateMachine1[] = {
    {evaluateSomething,         &ms1[1], &ms1[3], {startMotor,increaseSpeed,   NULL,         NULL, NULL, 3,5, 0, 0,0},
        {evaluateSomething,     &ms1[2], &ms2[0], {stopMotor, openExhaust,     decreaseSpeed,NULL, NULL, 1,20,13,0,0},
            {evaluateSomething, &ms1[0], &ms1[2], {openRelay, writeStatusToLog,increaseSpeed,NULL, NULL, 4,5, 87,0,0},
        {evaluateSomething,     &ms1[4], &ms2[1], {blah blah blah... },
            {evaluateSomething, &ms2[1], &ms2[2], {blah blah blah... },
};

struct myStruct_s myStateMachine2[] = {
    {evaluateSomething,         &ms2[1], &ms2[3], { blah blah blah... },
        {evaluateSomething,     &ms2[2], &ms3[0], { blah blah blah... },
            {evaluateSomething, &ms3[1], &ms3[3], { blah blah blah... },
        {evaluateSomething,     &ms2[4], &ms4[1], { blah blah blah... },
            {evaluateSomething, &ms4[0], &ms2[2], { blah blah blah... },
};

I am very happy with this code format, it make it very easy for me to follow where I am in the statemachine/flowchart and decide where to go next. My problem is that I need to port this code to a microcontroller that has little memory, so I would like to memory-optimize the code heavily. I have already replaced my action function pointers with an enum instead:

enum actionsToPerformInThisState_e {
    startMotor_,
    stopMotor_,
    openRelay_,
    openExhaust_,
    writeStatusToLog_,
    decreaseSpeed_,
    increaseSpeed_,
    NULL_
};

struct myStruct_s {
    returnTrueOrFalseFunctionPtr   trueOrFalse;
    struct myStruct_s*             whereToGoIfTrue;
    struct myStruct_s*             whereToGoIfFalse;
    actionsToPerformInThisState_e  actionToPerformInThisState0 : 3;
    actionsToPerformInThisState_e  actionToPerformInThisState1 : 3;
    actionsToPerformInThisState_e  actionToPerformInThisState2 : 3;
    actionsToPerformInThisState_e  actionToPerformInThisState3 : 3;
    actionsToPerformInThisState_e  actionToPerformInThisState4 : 3;
    int                            actionArguments[5];
};

What else can I do to reduce memory usage? Since most states don't use all 5 actions, I would like to have variable number of actions, but the elements in the array must be of same size, or can anybody think of a workaround (I can't place the actions outside the array and have a pointer to them because then the nice readability is lost). What about all pointers (each occupy a whopping 4 bytes!!!) to next states, can anybody think of another way to accomplish this linking? Other suggestions?

-- modified 9-Mar-18 15:17pm.

Re: How can I minimize memory usage in my table-based statemachine with several hundred states?

harold aptroot9-Mar-18 9:54

harold aptroot

9-Mar-18 9:54

Can the actionArguments have a narrower type? Maybe 5 chars instead of 5 ints?
The next-state pointers could be integers that index into the array of states instead of direct pointers, that would probably allow them to be uint16_t.
Maybe the pointer to the true/false function can be an enum too?

Re: How can I minimize memory usage in my table-based statemachine with several hundred states?

arnold_w9-Mar-18 10:00

arnold_w

9-Mar-18 10:00

harold aptroot wrote:
Can the actionArguments have a narrower type? Maybe 5 chars instead of 5 ints?
No, actionArguments can sometimes use 32 bits.

harold aptroot wrote:
The next-state pointers could be integers that index into the array of states instead of direct pointers, that would probably allow them to be uint16_t.
But how would I index when the pointer is pointing to a different array?

harold aptroot wrote:
Maybe the pointer to the true/false function can be an enum too?
Yes, of course, why didn't I think of that!

Re: How can I minimize memory usage in my table-based statemachine with several hundred states?

harold aptroot9-Mar-18 10:14

harold aptroot

9-Mar-18 10:14

arnold_w wrote:
actionArguments can sometimes use 32 bits.

OK. How often is that needed? Perhaps you can cheat a bit: allow only a couple of 32bit arguments, and the rest must be small. Then if one "block" of actions does need more 32bit arguments, it can be "split" into two successive states (which costs a lot of space, but if splitting is rare then it can be an overall win)
Or maybe: pack arguments in VLQ, but reserve a fixed amount of space. When it doesn't fit, split the state.

The next-state pointers could be integers that index into the array of states instead of direct pointers, that would probably allow them to be uint16_t.
But how would I index when the pointer is pointing to a different array?

OK maybe pack together two parts, some bits that indicate which array to look into, and some bits to indicate the index.

Re: How can I minimize memory usage in my table-based statemachine with several hundred states?

leon de boer9-Mar-18 15:16

leon de boer

9-Mar-18 15:16

You can tighten the structure at the cost of a carry an action size count. However it does allow you to use the same actions blocks for multiple states. That may often happen in that you just have things like confirm yes/no actions.

I also changed your pointer definitions to const as you are clearly going to have static tables and it will save compiler type casting errors.

I assume you are going to do this .. see the C11 initializers at code end which uses the standard _countof to autosize the arrays.
on GCC it's ARRAY_SIZE() but I hate the name so always define it _countof same as MSVC because it reflects better what it is IMHO.

typedef bool (*returnTrueOrFalseFunctionPtr) (void);
typedef void (*actionFunctionPtr) (int);

struct myAction_s {
	const actionFunctionPtr actionToPerformInThisState;
	const uint32_t actionArgument;
};

struct myStruct_s {
	returnTrueOrFalseFunctionPtr   trueOrFalse;
	const struct myStruct_s*       whereToGoIfTrue;
	const struct myStruct_s*       whereToGoIfFalse;
	const uint8_t				   maxActionsInThisState;    // Count of the actions in this state
	const struct myAction_s*	   actionsListInThisState;   // The action block pointer
 };

static void SomeYesFunc (int) {

}

static void SomeNoFunc(int) {

}

static void SomePerhapsFunc(int) {

}

static bool truefalseFunc(void) {
	return true;
}

/* ACTION BLOCK DEFINITIONS */
const struct myAction_s yesNoBlock[2] = { &SomeYesFunc, 1 , &SomeNoFunc, 2 };
const struct myAction_s yesNoPerhapsBlock[3] = { &SomeYesFunc, 1 , &SomeNoFunc, 2, &SomePerhapsFunc, 3};

/* ACTION STATE DEFINITIONS */
const struct myStruct_s nullState = { 0, 0, 0, 0, 0};
const struct myStruct_s yesNoState = { &truefalseFunc, &nullState , &nullState, _countof(yesNoBlock), &yesNoBlock[0] };
const struct myStruct_s yesNoPerhapsState = { &truefalseFunc, &nullState , &nullState, _countof(yesNoPerhapsBlock), &yesNoPerhapsBlock[0] };

In vino veritas

modified 9-Mar-18 21:53pm.

How to get object of a view which is created using AddView().

Sampath5799-Mar-18 0:38

Re: How to get object of a view which is created using AddView().

9-Mar-18 0:38

Hi
In my mfc application i created a window with multiple tabs as follows:

class MainWind: public CTabView
{
      void OnCreate(LPCREATESTRUCT lpstruct)
      {
           if (CTabView::OnCreate(lpCreateStruct) == -1)
		           return -1;

            AddView(RUNTIME_CLASS(CView1), _T("Sheet1"));
      }
}

class CView1 : public CScrollView
{
      CView1()
     {

     }
     void LoadData()
     {

     }
}

A window is created with one tab and CView1 is the view class for my window.
After AddView() i want to call LoadData() function which is available in CView1 class. May i know how to get the object of CView1 class in my MainWindclass.

Victor Nijegorodov9-Mar-18 1:45

Re: How to get object of a view which is created using AddView().

9-Mar-18 1:45

Can this discussion [RESOLVED] MDI CTabView help you?

Sampath57910-Mar-18 23:20

Re: How to get object of a view which is created using AddView().

10-Mar-18 23:20

No. I am unable to get that View object. Any other way?

Victor Nijegorodov11-Mar-18 2:05

Re: How to get object of a view which is created using AddView().

11-Mar-18 2:05

Then use the index returned by AddView. Suspicious | :suss:

Richard MacCutchan9-Mar-18 5:18

Re: How to get object of a view which is created using AddView().

9-Mar-18 5:18

You should capture the index value returned by CTabView::AddView[^]

Sampath57911-Mar-18 6:04

Re: How to get object of a view which is created using AddView().

11-Mar-18 6:04

I will get the index of view, but how to access that view using index.? I dint find any function like GetView(index) or something similar to it..

Victor Nijegorodov11-Mar-18 7:12

Re: How to get object of a view which is created using AddView().

11-Mar-18 7:12

Sampath579 wrote:
I will get the index of view, but how to access that view using index.? I dint find any function like GetView(index) or something similar to it..

You could try calling CTabView::SetActiveView followed by CTabView::GetActiveView

Richard MacCutchan11-Mar-18 22:32

How to release IDispatch memory.

11-Mar-18 22:32

Each call to AddView returns an index of the tab view. So when you want to make a particular view active you just call SetActiveView passing the relevant index value.

Sampath5797-Mar-18 2:45