DaniWeb Forum Index > Software Development > C++

C++ RSS

Converting array of longs to char []

Please support our C++ advertiser: Intel Parallel Studio Home

•

Join Date: Jun 2006

Posts: 1,169

Reputation: Duki has a spectacular aura about

Solved Threads: 9

Duki

Offline

Veteran Poster

Converting array of longs to char []

May 20th, 2009

I am trying to convert an array of longs to an array of chars. There are 1081 elements in the long array. Each element is 4 digits long. Is there a function in C++ that will convert a long something I can store in the array or could someone point me in the right direction? I'm not sure how to go about solving this one.

Thanks

It is practically impossible to teach good programming style to students that have had prior exposure to Basic; as potential programmers they are mentally mutilated beyond hope of regeneration.

-Edsger Dijkstra

•

Join Date: Aug 2005

Posts: 5,264

Reputation: iamthwee is a splendid one to behold

Solved Threads: 377

iamthwee

Offline

Posting Expert

Re: Converting array of longs to char []

May 20th, 2009

Dunno how about converting a double to a string, such as stringstream.

*Voted best profile in the world*

•

Join Date: Apr 2008

Posts: 38

Reputation: _Nestor is an unknown quantity at this point

Solved Threads: 4

_Nestor

Offline

Light Poster

Re: Converting array of longs to char []

May 20th, 2009

I think this should answer your question
http://www.codeguru.com/forum/showthread.php?t=231056

•

Join Date: Jun 2006

Posts: 1,169

Reputation: Duki has a spectacular aura about

Solved Threads: 9

Duki

Offline

Veteran Poster

Re: Converting array of longs to char []

May 20th, 2009

So let me see if I understand this. If I use

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
template <class T>
std::string to_string(T t, std::ios_base & (*f)(std::ios_base&))
{
  std::ostringstream oss;
  oss << f << t;
  return oss.str();
}
template <class T>
std::string to_string(T t, std::ios_base & (*f)(std::ios_base&))
{
  std::ostringstream oss;
  oss << f << t;
  return oss.str();
}

I should be able to pass this function a long and it will convert it to a string.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
cout<<to_string<long>(123456, std::string)<<std::endl;
cout<<to_string<long>(123456, std::string)<<std::endl;

•

Join Date: Oct 2008

Posts: 2,610

Reputation: adatapost has much to be proud of

Solved Threads: 460

adatapost

Offline

Posting Maven

Re: Converting array of longs to char []

-1

May 20th, 2009

•

Originally Posted by Duki

I am trying to convert an array of longs to an array of chars. There are 1081 elements in the long array. Each element is 4 digits long. Is there a function in C++ that will convert a long something I can store in the array or could someone point me in the right direction? I'm not sure how to go about solving this one.

Thanks

Yes, it is.

Here is a code.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
  char *p;
  long a[4]={1,1,1,1};
  int i=0;
  p=(char *)a;
 
  while(i<16)
   {
      printf("\n%c",*(p+i));
      i++;
   }
  char *p;
  long a[4]={1,1,1,1};
  int i=0;
  p=(char *)a;

  while(i<16)
   {
      printf("\n%c",*(p+i));
      i++;
   }

Failure is not fatal, but failure to change might be. - John Wooden

•

Join Date: Oct 2008

Posts: 2,610

Reputation: adatapost has much to be proud of

Solved Threads: 460

adatapost

Offline

Posting Maven

Re: Converting array of longs to char []

-1

May 20th, 2009

tux4life >Unportable rubbish which doesn't work.
adatapost>Oh!!! Buddy you should have to test this code before judge.

Failure is not fatal, but failure to change might be. - John Wooden

•

Join Date: Feb 2009

Posts: 1,968

Reputation: tux4life has a reputation beyond repute

Solved Threads: 214

tux4life

Offline

Posting Virtuoso

Re: Converting array of longs to char []

May 20th, 2009

•

Originally Posted by adatapost

tux4life >Unportable rubbish which doesn't work.
adatapost>Oh!!! Buddy you should have to test this code before judge.

I have tested it before I judged, I'm not stupid ...

"Never argue with idiots, they just drag you down to their level and then beat you with experience."

•

Join Date: Apr 2004

Posts: 4,342

Reputation: Dave Sinkula has a brilliant future

Solved Threads: 237

Dave Sinkula Dave Sinkula is offline

Offline

long time no c

Re: Converting array of longs to char []

May 20th, 2009

•

Originally Posted by Duki

I am trying to convert an array of longs to an array of chars. There are 1081 elements in the long array. Each element is 4 digits long. Is there a function in C++ that will convert a long something I can store in the array or could someone point me in the right direction? I'm not sure how to go about solving this one.

Perhaps you could try to clarify what it is you are attempting to do.

By each element, I assume you mean each long integer. By 4 digits long, do you mean the values are 1234 , 5678 , etc.?

By convert to char[], do you mean convert to a 5-element C-style string? To a std::string? Other?

Or do you mean you would like to display the underlying hexadecimal representation of the value -- such as the decimal 1234567890 being equivalent to 499602D2 in hexadecimal (4 bytes in this case)?

And, what is the larger picture? That is, have you chosen an assumed solution without fully understanding the problem?

"One of the methods used by statists to destroy capitalism consists in establishing controls that tie a given industry hand and foot, making it unable to solve its problems, then declaring that freedom has failed and stronger controls are necessary." --Ayn Rand

•

Join Date: Oct 2006

Posts: 2,832

Reputation: niek_e has a reputation beyond repute

Solved Threads: 297

niek_e

Online

Roasting Maven

Re: Converting array of longs to char []

May 20th, 2009

•

Originally Posted by Duki

I am trying to convert an array of longs to an array of chars. There are 1081 elements in the long array. Each element is 4 digits long.

So if I understand correct: These number vary from 0 to 9999?
A single char can only hold values up to 255, so it's not possible to hold the value in a single char.
If you want to convert each long to a char-array (so create a 2d array), you could use stringstreams as mentioned by iamthwee, or you could do it with bitwise operators. (or even sprintf....)

[edit] Dave beat me to it...

Last edited by niek_e; May 20th, 2009 at 2:03 pm.

•

Join Date: Jun 2006

Posts: 1,169

Reputation: Duki has a spectacular aura about

Solved Threads: 9

Duki

Offline

Veteran Poster

Re: Converting array of longs to char []

#10

May 20th, 2009

Sorry for the confusion. Let me try to clarify it a little. What I'm trying to do is to get two already written programs to work together. I have one program that gets data from a Laser Measurement System. It reports its values in an array of longs. I need to send these vaules to another program. I have some code that will send a char* via udp ports (using the sendto() function). So I thought that I could convert the each long to something that my code could send to the other program.

I may be doing this completely wrong, so if you know of a better way to do this please let me know. The only reason that I'm doing it this way is because of time constraints and limited knowledge of this type of programming.

Hope this helps