Using Math Parser in C++ Builder
For those of you who know C++, but are not very familiar with Delphi, here is a C++ Builder Example that shows how to create a custom function that takes 3 parameters and use it in the expression.
In bcParser.hpp, we have the following definitions:
virtual void __fastcall
CreateNParamFunc(const AnsiString name, TNParamFunc
procAddr, int nParam);
we also have:
typedef Extended __fastcall (*TNParamFunc)(const Extended * x, const int x_Size);
Therefore, you define a function as:
Extended __fastcall sumof3(const Extended * x, const int x_Size)
{
return x[0]+x[1]+x[2];
}
//And use it as:
void __fastcall TForm1::Button1Click(TObject *Sender)
{
bcParser1->Expression = Edit1->Text;
if(!bcParser1->IsFunction("SUM3")){
//define a 3 parameter function.
bcParser1->CreateNParamFunc("SUM3", sumof3, 3);
}
Label1->Caption = FloatToStr(bcParser1->Value);
}
|
