How to convert DataObject type to other data type?

[antangzhu]

Hello,
i have following codes:

#include "clipscpp.h"
#include <iostream>
using namespace CLIPS;
using namespace std;
int main()
{
CLIPSCPPEnv theEnv;
DataObject theData1;
theEnv.Load("test01.clp");
theEnv.Reset();
theEnv.Run(-1);
theData1 = theEnv.Eval("(fact-slot-value 2 R)");
cout<<theData1 <<endl;
}

i can see the result of theData1 is 1.77 from the screen, but i also
want to convert theData1 to double type of C++ in order to pass
theData1 to external C++ function to use. what should i do ?
Thanks!

[Lode Hoste]

HI Antangzhu,

Please read the advanced programming guide: 4.1.9 Eval.

<<<
int Eval(expressionString,&result);
Arguments:
1) A string containing the expression to be evaluated.
2) Caller’s buffer for storing the result of the evaluation. See
sections 3.2.3 and 3.2.4 for information on getting the value
stored in a DATA_OBJECT.
>>>

Once you have a DATA_OBJECT, you can easily get the double value.
Note that the documentation was for CLIPS (C) while you are using
CLIPSCPP but it should be more or less the similar.

2012/5/24 antangzhu <zhangyu...@gmail.com>:

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