Parsing in C - C / C++ / MFC Discussion Boards

Re: WS_TABSTOP

jkirkerx9-Dec-11 16:34

jkirkerx

9-Dec-11 16:34

So I spent a whole day writing all that for nothing?

Why does all the functionality that I wrote still works?

Re: WS_TABSTOP

Stephen Hewitt9-Dec-11 19:42

Stephen Hewitt

9-Dec-11 19:42

Firstly, have you tried the code I posted and does it work for you?
"Nothing" is a bit strong, you no doubt learnt something.
As to why it works, that's better explained in the original link I posted, in short it's because that's what the function is for.

Steve

Re: WS_TABSTOP

jkirkerx9-Dec-11 20:18

jkirkerx

9-Dec-11 20:18

All the functionality that I wrote works with 4 lines of your code.

Just upset because time is finite, and yes I did learn something, but at what price?.

Don't take it personally if I don't sound grateful. Give me a day to cool off.

I was so proud of myself for figuring it out, only to find out that I could of just bent time and space instead of traveling a great distance across the universe.

Re: WS_TABSTOP

Stephen Hewitt9-Dec-11 21:22

Stephen Hewitt

9-Dec-11 21:22

No offense taken. Every programer as had that experience.

Steve

It works, now but how to detect shift tab <<

jkirkerx8-Dec-11 12:40

jkirkerx

8-Dec-11 12:40

Yeah it works now, but I want to backwards to.

How to detect shift + tab, or pull it out of the message

// Intercept the Messages I want to hear
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);

        if (msg.message == WM_CHAR) {
            // Tab motion forward >>
            if (msg.wParam == VK_TAB) {
                SetFocus(GetNextDlgTabItem(hManage_CreateAccount, GetFocus(), FALSE));
            }
            // Tab motion backwards <<
            else if ((msg.wParam == VK_TAB) && (msg.lParam == VK_SHIFT)) {
                SetFocus(GetNextDlgTabItem(hManage_CreateAccount, GetFocus(), TRUE));
            }
        }
    }

Re: It works, now but how to detect shift tab <<

Graham Breach8-Dec-11 13:06

Graham Breach

8-Dec-11 13:06

Obviously wParam can't be both VK_TAB and VK_SHIFT at the same time, so you'll have to check if shift is being held down when tab is pressed. Try using GetKeyState()[^]

Room for improvement let me know.

jkirkerx8-Dec-11 13:16

jkirkerx

8-Dec-11 13:16

I just figured that out, maybe I can detect the ks in a better way, something about the high and low order. but it goes forward and backwards now, and in my MDI Child window. So I don't have to dump my GUI's and convert them to dialogs.

Lesson hard learned after reading all those articles and tips.

while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);

        if (msg.message == WM_CHAR) {
            short ks = GetKeyState(VK_SHIFT);
            if (msg.wParam == VK_TAB) {
                if (ks >= 0) {
                    // Tab motion forward >>
                    SetFocus(GetNextDlgTabItem(hManage_CreateAccount, GetFocus(), FALSE));
                }
                else {
                    // Tab motion backward <<
                    SetFocus(GetNextDlgTabItem(hManage_CreateAccount, GetFocus(), TRUE));
                }
            }
        }
    }

Parsing in C

Software20077-Dec-11 6:55

Software2007

7-Dec-11 6:55

I know how to do this in C++, but a bit rusty on C,
char line[1024]="d(Text1)b(ID1)n(node1)d(Text2)b(ID2)n(node2)d(Text3)b(ID3)n(node3)...
I would like to parse the line above into item0 = d(Text1)b(ID1)n(node1), item2 - d(Text2)b(ID2)n(node2)... and so forth

char *py;
char *px = line;
while ((py=strstr(px,"d(")) != NULL) {
    //   if ((px=strstr(py,")")) == NULL)
    //       printf("error1");
       px++;
       }

return 0;

Thanks

Re: Parsing in C

Albert Holguin7-Dec-11 7:23

Albert Holguin

7-Dec-11 7:23

Did you try sprintf()?
http://www.cplusplus.com/reference/clibrary/cstdio/sprintf/[^]

Re: Parsing in C

C^hris L^osinger7-Dec-11 8:10

C^hris L^osinger

7-Dec-11 8:10

so, is it "n(nodename)" that signals the end of a 'node' and "d(whatever)" for the start?

i always find state-machines the easiest way to do simple parsing.

off the top of my head...

typedef struct item_t
{
   char d[100];
   char b[100];
   char n[100];
} item;

const char *consume_between_parens(const char *p, char *out)
{
   if (*p!='(') return NULL; // error

   p++;
   while (*p)
   {
       if (p==')') // done
       {  
           p++;
           break;
       }
       *out = *p; // copy
       out++; p++; // next
   }

   return p;
}

void parse(const char *p, itemArray array ... some array thing)
{
  enum {wantD, wantB, wantN} state = wantD;

  item * curItem = null;

  while (*p)
  {
     switch (state)
     {
         case wantD:  // we need a 'd'
            if (*p=='d')
            {
                curItem = malloc(sizeof(item));
                p = consume_between_parens(p, curItem->d);
                state = wantB;
            }
            else error
            break;
         case wantB:  // we need a 'b'
            if (*p=='b')
            {
                p = consume_between_parens(p, curItem->b);
                state = wantN;
            }
            else error
         case wantN:  // we need an 'n'
            if (*p=='n')
            {
                p = consume_between_parens(p, curItem->n);
                addToArray(array, curItem);
                state = wantD;
            }
            else error
            break;
         default: 
            error;
     }
     p++;
  }
while

image processing toolkits | batch image processing

Re: Parsing in C

Software20077-Dec-11 9:54

Software2007

7-Dec-11 9:54

Fantastic! I did get it to work with very minor modifications.

C++

typedef struct item_t
{
   char d[8192];
   char n[8192];
   char i[8192];
} item;

char *consume_between_parens(char *p, char *out)
{
   p++;   //advance to where we think there is '('

   if (*p!='(') return NULL; // error

   int paren_count = 1;

   p++;
   while (*p)
   {
	   if (*p=='(') 
          paren_count++;

       if (*p==')') 
          paren_count--;

	   if(!paren_count) //done
		   break;

       *out = *p; // copy
       out++; p++; // next
   }
 
   return p;
}


void parse(char *p)
{

  item * curItem = NULL;
 
  while (*p)
  {

            if (*p=='d')
            {
                curItem = (item*)malloc(sizeof(item));
                p = consume_between_parens(p, curItem->d);
            }
            if (*p=='n')
            {
                p = consume_between_parens(p, curItem->n);
            }
            if (*p=='i')
            {
                p = consume_between_parens(p, curItem->i);
               // addToArray(array, curItem);
            }

     p++;
  }

}

int _tmain(int argc, _TCHAR* argv[])
{
	char *text ="1:7\22\\d(2011)n(0)i(711910)d(2010)n(1)i(711911)";

	parse(text);

	return 0;
}

Re: Parsing in C

David Crow7-Dec-11 9:27

David Crow

7-Dec-11 9:27

Have you looked at strtok()?

"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

"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous

Re: Parsing in C

Software200710-Dec-11 13:28

Software2007

10-Dec-11 13:28

I just did. Thanks for mentioning it, this function actually makes things a lot easier, since it does most of the pointer work for you. I will give it a try.
Thanks again

Re: Parsing in C

Software200712-Dec-11 5:52

Software2007

12-Dec-11 5:52

I have one more question C- related:

C++

char *getLine(char *p, char *out)
{
   int Dees = 0;
   char *px = p;
   p++;   //advance to where we think there is '('
 
   if (*p!='(') return NULL; // error
 
   int paren_count = 1;
 
   while (*px)
   {
                   if(*px=='d')
                   {
                                   Dees++;
                                   if(Dees >1 && *(px+1)=='(') //Done at 2nd 'd'
                                      break;
                   }
 
       *out = *px; // copy
       out++; px++; // next
   }
   return px;
}

//main program
  char *px="d(text)n(0)l(1)d(text2)n(1)l(2)...";
  char line[8192];
  char *py = getLine(px,line);

In the main program, after calling the function getLine(), I do get line correctly as in "d(text)n(0)l(1)" but filled with garbage after that as its trying to fill out 8192 characters. How do I make it not fill the rest of the unused space. Note, I don't know the size of "line" as it varies, but I need it big enough. I know strcpy could be useful here somewhere, just can't get it to work.

I also tried in getLine() the following:

char field[4095];
 strcpy(field,out);

But nothing gets copied, out shows null in the debugger.

Thanks

modified 12-Dec-11 12:00pm.

Re: Parsing in C

David Crow12-Dec-11 7:15

David Crow

12-Dec-11 7:15

After the while() loop, you need to terminate out with a '\0' character.

modified 12-Dec-11 14:26pm.

Re: Parsing in C

Software200712-Dec-11 7:32

Software2007

12-Dec-11 7:32

Fabulous!

C++

while (*px != '\0')

did the trick. I have to admit i don't quite get it though, In the string "d(2011)n(0)i(711910)d(2010)n(1)i(711911)", I am telling to break out when it sees the next 'd(', so why do I need the terminating character? Could you clarify?

Thanks much

Re: Parsing in C

David Crow12-Dec-11 8:34

David Crow

12-Dec-11 8:34

Software2007 wrote:
C++
while (*px != '\0')
did the trick.

Not sure how, since these three staments are identical:

while (*px)
while (*px != 0)
while (*px != '\0')

What you should have done instead is add a '\0' character to out after the while() loop. That way, it'll be properly (i.e., null) terminated.

Re: Parsing in C

Software200712-Dec-11 9:36

Software2007

12-Dec-11 9:36

Great, makes sense.

Double value precision

mutpan6-Dec-11 18:54

mutpan

6-Dec-11 18:54

Hello All, I am using visual studio 2008 and maniplulating double addition.

C++

double a = 1.5000010
double b = 0.0000090;
double c = a+b;

The output I am expecting here is 1.5000100 but the actual output comes as 1.5000099999999998.

I dont have to consider more than 7 fractional points so the it looks like 1.5000099.

How do i convert or store this in to the format which i like? that means 1.5000100.

Is there any built-in method or win32 API available to do this?

Thanks in advance.

Re: Double value precision

Chandrasekharan P6-Dec-11 19:27

Chandrasekharan P

6-Dec-11 19:27

May be this will help you

C++

#include<stdio.h>
void main()
{
	double a,b,c;
	a = 1.5000010;
	b = 0.0000090;
	c = a + b;
	printf("%.7f\n",c);
}

Every new day is another chance to change your life.

Re: Double value precision

mutpan6-Dec-11 19:35

mutpan

6-Dec-11 19:35

Hi Chandrasekhran, thanks for your reply.
I want to store this in to another double variable for calculation and not for printing in to console.

Re: Double value precision

Chandrasekharan P6-Dec-11 20:33

Chandrasekharan P

6-Dec-11 20:33

Maybe its a roundabout way.

Use the sprintf and save the result in a buffer.

sprintf(buffer,"%.7f\n",c);

Then convert the buffer which is a char array to double using "atof"

d = atof(buffer);

where "d" is a double data type.

and then use d in your calculations.

Every new day is another chance to change your life.

Re: Double value precision

CPallini6-Dec-11 22:13

CPallini

6-Dec-11 22:13

mutpan wrote:
How do i convert or store this in to the format which i like? that means 1.5000100.

You shouldn't do that.
You should store it 'as is' and use 'the format I like' just when you need to output it.

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: Double value precision

Albert Holguin7-Dec-11 3:24

Albert Holguin

7-Dec-11 3:24

Good point Thumbs Up | :thumbsup:

Re: Double value precision

tssutha036-Dec-11 22:30

tssutha03

6-Dec-11 22:30

http://stackoverflow.com/questions/798046/digit-limitation-from-decimal-point-in-c[^]

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.