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May 20th, 2009

Converting array of longs to char []

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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

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Duki

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May 20th, 2009

Re: Converting array of longs to char []

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

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May 20th, 2009

Re: Converting array of longs to char []

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

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May 20th, 2009

Re: Converting array of longs to char []

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

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.

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

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Re: Converting array of longs to char []

Click to Expand / Collapse Quote 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.

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++;
   }

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May 20th, 2009

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Re: Converting array of longs to char []

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

adatapost

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Re: Converting array of longs to char []

Click to Expand / Collapse Quote 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 ...

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May 20th, 2009

Re: Converting array of longs to char []

Click to Expand / Collapse Quote 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?

Dave Sinkula

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May 20th, 2009

Re: Converting array of longs to char []

Click to Expand / Collapse Quote 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 Nick Evan; May 20th, 2009 at 2:03 pm.

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May 20th, 2009

Re: Converting array of longs to char []

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

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