C / C++ / MFC

int n = sqrt(3); // error C2668: 'sqrt' : ambiguous call to overloaded function

double d = sqrt(2.0); // no error - return value and passed argument are doubles

int n = (int)sqrt((double)3);  // no error (except loss of precision converting double to int)

Mark Salsbery
Microsoft MVP - Visual C++

George_George wrote:

1.

The following compiler error from the following code segment, is because delete statement from destructor of auto_ptr requires the declaration of destructor of wrapped object?

George_George wrote:

we should declare (not necessary to implement) constructor and destructor before using new to create the object, right?

Rajkumar R wrote:

but any member

#include <memory>
#include <iostream>

using namespace std;

class Foo {
public:
	Foo();
	~Foo();
};

void func()
{

	auto_ptr<Foo> pf (new Foo());

	cout << "I am here. " << endl;

	return;
}

int main()
{
	func();

	return 0;
}

Foo::Foo()
{
}

Foo::~Foo()
{
}

using namespace std;
class Foo; // forward declaration

void func()
{
  auto_ptr<Foo> pf (new Foo());	
  cout << "I am here. " << endl;
  return;
}
int main()
{
  func();	
  return 0;
}
// full declaration of class Foo
class Foo 
{
 public:
	Foo();
	~Foo();
};

Foo::Foo()
{}

Foo::~Foo()
{}

alphaxz wrote:

I use the class in a global function
then i deifne the global function as export function

Mark Salsbery
Microsoft MVP - Visual C++

// MyClass.h

#if defined(BUILDING_MY_DLL)
  #define MY_DLL_IMP_EXP __declspec(dllexport)
#else
  #define MY_DLL_IMP_EXP __declspec(dllimport)
#endif

class MyClass
{
public:
	MY_DLL_IMP_EXP int SomeFunc();
};

#include "MyClass.h"

int MyClass::SomeFunc()
{
	return 12;
}

#include "MyClass.h"

MyClass mc;
int ret = mc.SomeFunc();

Mark Salsbery
Microsoft MVP - Visual C++

Member 2021022 wrote:

I wasn't aware that there were new extensions syntax

typedef array<float> floatArray;
...
// create a floatArray with 10 elements
floatArray ^farray = gcnew floatArray(10);

Member 2021022 wrote:

I thought I had published it to the C++ board

Mark Salsbery
Microsoft MVP - Visual C++