Databases
StackOverflow2013
Postsdbo
POconvert doubles from a text file into a binary file
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POconvert doubles from a text file into a binary file
    primarykey
    data
    text
    <p>I have a text file full of numbers (from a molecular dynamics output, should be type <code>double</code>) divided in three columns and with thousands of lines like this:</p> <pre><code> -11.979920 -13.987064 -0.608777 -9.174895 -13.979109 -0.809622 </code></pre> <p>I want to read all the numbers in the file, convert them to type <code>double</code> and then save them into a <code>binary</code> file. I know that binary file is not recommended, but I want it to test compression algorithms with both file formats, i.e text and binary. I have tried with <a href="https://stackoverflow.com/questions/5016262/need-to-convert-txt-file-into-binary-file-in-c">Need to convert txt file into binary file in C++</a> but I am not sure if is converting each number in its whole format: -11.275804 or if it is parsing each individual number: -1,1,2,7,5, etc..</p> <p>Edit: Have been trying to convert a single double to binary and back, there are some problems. Here's the core code</p> <pre><code> if( std::string(argv[1]) == "-2bin") //convert to binary { cout &lt;&lt; "Performing the conversion: Text -&gt; Binary..." &lt;&lt; endl; std::ifstream in(argv[2]); std::ofstream out(argv[3], std::ios::binary); double d; while(in &gt;&gt; d) { cout &lt;&lt; "read a double: "&lt;&lt; d &lt;&lt;endl; out.write((char*)&amp;d, sizeof d); } out.flush(); out.close(); cout &lt;&lt; "Conversion complete!" &lt;&lt; endl; return 0; }else if( std::string(argv[1]) == "-2text" ) //convert to text { cout &lt;&lt; "Performing the conversion: Binary -&gt; Text..." &lt;&lt; endl; std::ifstream in(argv[2], std::ios::binary); std::ofstream out(argv[3]); std::string s; while(in &gt;&gt; s) { cout &lt;&lt; "read a string:" &lt;&lt; s &lt;&lt;endl; out.write((char*)&amp;s, s.length()); } out.flush(); out.close(); cout &lt;&lt; "Conversion complete!" &lt;&lt; endl; return 0; </code></pre> <p>When reading only one double, for example <code>1.23456789</code> the read string is just of length 7</p> <pre><code>read a double: 1.23457 </code></pre> <p>I want it to read until the next 'space' and then do the conversion to double->bin. When doing the binary -> text conversion everything is just broken, I don't know how to handle the binary and convert it to double and then string.</p> <p>Update: Finally I managed to check that the binary conversion is working with <code>od -lF</code> utility, but every each line there is a strange line that I have no idea what it means, it cuts the zero from the first number and the output comes in two columns instead of 3:</p> <pre><code>od -lF composite_of10_2.bin | more 0000000 -4600438323394026364 -4599308401772716498 -11.97992 -13.987064 0000020 -4619713441568795935 -4602017412087121980 -0.608777 -9.174895 0000040 -4599312880039595965 -4617904390634477481 -13.979109 -0.809622 </code></pre> <p>Does this look correctly converted? How should I perform the conversion from binary to double string?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USCommunity
    1. USSamGamgee
    plurals
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POconvert doubles from a text file into a binary file
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POconvert doubles from a text file into a binary file
      1. This table or related slice is empty.
      1. VTDownMod
    3. VO
      singulars
      1. POconvert doubles from a text file into a binary file
      1. This table or related slice is empty.
      1. VTUpMod
    1. COYou can easily check it by writing one number using the methods shown in the post you linked to and then read back the file one byte at a time. If the bytes read are the ASCII codes for the digits then it has not converted the number.
      singulars
      1. POconvert doubles from a text file into a binary file
      1. USAndrew Morton
    2. CO-1 because it seems the OP has not given this an honest effort. @SamGamgee if you have indeed already tried, please edit the question to include more detail -- i.e. what have you done, what were the results, why were the results wrong -- and I will gladly remove the downvote. I'd also suggest basic software engineering, like using really small test cases: 1) can you parse a single double correctly; 2) can you write a double to binary format correctly; 3) can you read a double from binary correctly, etc.
      singulars
      1. POconvert doubles from a text file into a binary file
      1. USMatt Fenwick
    3. COOk I spent some more time trying to figure it out how it works, but so far this is what I was able to achieve. Added the code and the output to the post.
      singulars
      1. POconvert doubles from a text file into a binary file
      1. USSamGamgee
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload