Hello!

Please help me correct the error:

error C2230: 'GenerateRandomHReal': it doesn’t mean an aggregate

I am writing a project based on the Windows Form Application. NET in Microsoft Visual C ++. NET 2003. The program logic is implemented directly in the class Form file Form1.h (I understand, not very correctly, but these are details). The program at the touch of a button fills the matrix with random numbers and performs some calculations. There is a third-party math library written in non-managed C ++. This library describes the data type (high accuracy) HReal. It turns out that, as it were, in managed C ++ (__gc class Form1), a function method is used that takes arguments and returns the value of an unmanaged HReal type. So this error is issued. But how to fix it?

I read, stumbled upon such concepts as: 1) the template class gcroot <TYPE>, the structure of GCHandle; 2) writing a wrappera for a class; 3) use of # pragma managed and # pragma unmanaged directives to combine managed and unmanaged C ++ in one module.

Tell me how to fix, maybe using the above concepts? Or am I looking in the wrong direction? Tell me please! Thank!

#include <string.h> #include <cstringt.h> #include <afxwin.h> #using <mscorlib.dll> #pragma once namespace SolveSLAU { using namespace std; using namespace System; using namespace System::ComponentModel; using namespace System::Collections; using namespace System::Windows::Forms; using namespace System::Data; using namespace System::Drawing; public __gc class Form1 : public System::Windows::Forms::Form { // Глобальные переменные private: bool IsButton1Pressed; bool IsMatrixSet; // Флаг: "Матрица уже инициализирована?" HReal **A01, **A02, *B01, *B02, *X1_2, *X2_1; double Eps; // Точность расчетов Эпсилон int m1, m2, n0; int MantissPrecision; // Точность мантиссы private: System::Void button1_Click(System::Object * sender, System::EventArgs * e) { int n = 0, i,j; HReal ** A1, ** A2, *X1; HReal * B1, * B2, *X2; HReal alfa_0, alfa_1; CString myStr1(""); CString myStr2(""); CString myStr3(""); CString myStr0(""); CString myspace(" "); MantissPrecision = System::Int32::Parse(this->textBox1->Text); Eps = System::Double::Parse(this->textBox2->Text); ***** this->listBox6->Items->Add(System::Convert::ToString(myStr0)); X1[i] = GenerateRandomHReal(alfa_0, alfa_1, MantissPrecision); X1_2[i] = GenerateRandomHReal(alfa_0, alfa_1, MantissPrecision); myStr0.Format(_T("%lf\n"), X1[i] ); this->listBox2->Items->Add(System::Convert::ToString(myStr0)); X2[i] = GenerateRandomHReal(alfa_0, alfa_1, MantissPrecision); X2_1[i] = GenerateRandomHReal(alfa_0, alfa_1, MantissPrecision); myStr0.Format(_T("%lf\n"), X2[i] ); this->listBox5->Items->Add(System::Convert::ToString(myStr0)); } } else { // -------------------- генератор ---------------- private: gcroot<HReal> GenerateRandomHReal(const gcroot<HReal> &a, const gcroot<HReal> &b, int MantissPrecision) // [a,b] - диапазон { CString s = "0.", s1; int j; for (int i = 0; i < MantissPrecision; i++) { j = rand() % 10; s1.Format("%i", j); s += s1; } HReal result(s); return a + result * (b - a); }

    1 answer 1

    The easiest way is to make GenerateRandomHReal separate function, that is, take it out of the Form1 class. Remember that it should be visible at the point where you use it, so declare it before the start of the class.

    In general, you write in C ++ / CLI, which is absolutely terrible. No wonder you have problems with it. If you need a UI, go to C #, it is much easier than C ++, and you can forget about all the horrors like gcroot . Or vice versa, write in pure C ++, unmanaged console applications.

    C ++ / CLI is intended only to write simple small wrappers for native functions on it so that it is easy to work with them from under C #.