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how to convert string type to scalar type

Hello everyone,

In a small post-processing program, I have to convert a string into a scalar:

Code:

int main(int argc, char *argv[])

{

    timeSelector::addOptions();

    argList::validArgs.append("fieldName"); 

    argList::validArgs.append("xValue");

#   include "setRootCase.H"

#   include "createTime.H"

    instantList timeDirs = timeSelector::select0(runTime, args);

#   include "createMesh.H"



    word fieldName(args.additionalArgs()[0]);

   word xValue(args.additionalArgs()[1]);

    

    Info <<xValue<<endl;

    

    ......     // ?

   scalar   x=       //   get the value from xValue, but xValue is a string---How???

Thanks for any help!

You could use 'strtod' from the cstdlib.

http://www.cplusplus.com/reference/c...stdlib/strtod/

I add the following,It worked.Thank you very much.

Code:

 #include <cstdlib>

...

   char* pEnd;

   scalar x=strtod(xValue.c_str(),&pEnd);

Convert to double

Hello, i got a similar problem.

I am trying to read from values from the thermophysical properties file.

Here is my code:
const fvMesh &PoP99 = V_.db().parent().objectRegistry::lookupObject<fvMe sh>(region2);
const dictionary t1 = PoP99.thisDb().lookupObject<IOdictionary>("thermop hysicalProperties");

const dictionary t2(t1.subDict("mixture"));
const dictionary transpks(t2.subDict("transport"));
const auto sigmaLayer = transpks.lookup("sigmaL");
const auto st = sigmaLayer[0];

double q = 10.0;

Info << st*q <<endl;

obviously this dosent work because st has the datatype Foam::token amd q double.

is there a way to convert from Foam::token to double?

Quote:

Originally Posted by Rudiy (Post 854390)

Not really sure what your "sigmaL" represents. At the moment it simply represents a copy of a tokenList (which is the ITstream that the lookup method returns). If we assume that "sigmaL" is actually supposed to be a list of scalars I would write it like this:

Code:

const fvMesh &PoP99 = V_.db().parent().objectRegistry::lookupObject<fvMe  sh>(region2);

  const dictionary& t1 = PoP99.thisDb().lookupObject<IOdictionary>("thermop  hysicalProperties");



  const dictionary& t2 = t1.subDict("mixture");

  const dictionary& transpks = t2.subDict("transport");

  const scalarList sigmaLayer = transpks.get<scalarList>("sigmaL");

  const scalar st = sigmaLayer[0];

Note that this also avoids making copies of the dictionaries like your original code did.

Hello,

Thanks for your code, i manged to get it to work with a similar version.
.get... did not work for me. I used this insted:

scalar sigmaLayer (readScalar(transpks.lookup("sigmaL")));

thanks for the help

Quote:

Originally Posted by Rudiy (Post 854459)

Glad you have it working. If you get a newer version, the dictionary get method is preferred since it will also check if there were any trailing tokens.

ok good to know, thaks for the advice.

Unfortunately the get() function didnt work. The code compiled without any errors, but when i run the openFoam case i get the following Error:

--> FOAM FATAL IO ERROR: (openfoam-2212)
attempt to read beyond EOF

file: constant/solidR/thermophysicalProperties.electricalProperties.elek transport.sigmaL at line 60.

From virtual Foam::Istream& Foam::ITstream::read(Foam::token&)
in file db/IOstreams/Tstreams/ITstream.C at line 450.

FOAM exiting