I'm using eclipse and messing around with complex numbers. I am not sure how to do this. I know how to do an integer and a double but not the complex type. I found something that said to do
Complex c= new Complex(1.0.3.0); // 1+3i
but that doesnt quite work out. It just gives an error that says the constructor is undefined?
Do you have a Complex.class file in the same folder as your other code?
I grabbed a Complex class from here, created the Complex.class file with javac Complex.java and then running the following code (filenames example.java and example.class) was not a problem:
class example {
public static void main(String [] args) {
Complex a = new Complex(1,2);
}
}
Related
I've tried to find any info on that but failed, maybe someone here can help.
I'm using IzPack 5 since couple of weeks and that's what I started with, so I have no prior IzPack 4 experience.
What I want to do is the following:
Give the user an opportunity to select data directory via
UserInputPanel (works fine)
Validate the entry by checking if the
database already resides there (works fine)
Depending on whether
the DB already exists and if "force" flag specified on the
UserInputPanel create the database after the packs have been
installed
This last step, that's what I can't see how to do.
I hava a java class that implements InstallerListener interface:
public class IzPackInstaller implements com.izforge.izpack.api.data.DynamicInstallerRequirementValidator,
com.izforge.izpack.api.event.InstallerListener {
It's the same class I use for both data validation / db existance check on step 2 and creation on step 3, just for convinience reasons, but it shouldn't matter
I override
#Override
public void afterInstallerInitialization(AutomatedInstallData data)
throws Exception {
System.out.println("Called afterInstallerInitialization");
System.out.println("db.location=" + data.getVariable("db.location"));
System.out.println("db.force.creation=" + data.getVariable("db.force.creation"));
}
but it seems to be deprecated alltogether and is never called in runtime - checked with System.out's.
The same is valid for:
#Override
public void afterPacks(AutomatedInstallData data,
AbstractUIProgressHandler handler) throws Exception {
System.out.println("Never called!");
}
I also override
#Override
public void afterPacks(List<Pack> packs, ProgressListener listener) { }
which is called allright, but how to get hold of AutomatedInstallData within this method? Or how else can I read installer variables at this stage?
I thought of creating a singleton, which I would initialize with the variables during DynamicInstallerRequirementValidator.validateData() call and get the variables at a later point in time, but it's ugly and sounds like a nasty workaround - there should be a way to implement InstallerListener interface and be able to use the variables, shouldn't it?
I'd be really grateful for any hints...
Anton
This is not a very clean solution but there is a way to get a hold of AutomatedInstallData really anywhere in running izpack java without actually overriding some method etc. I would just not suggest it in the first place because it is a little tricky :)
public class Test {
InstallerContainer container = new ConsoleInstallerContainer();
AutomatedInstaller automatedInstaller = container.getComponent(AutomatedInstaller.class);
AutomatedInstallData installData;
public Test() throws IllegalAccessException, NoSuchFieldException {
Field f = AutomatedInstaller.class.getDeclaredField("installData");
f.setAccessible(true);
installData = (AutomatedInstallData)f.get(automatedInstaller);
}
etc...
Now you will have access to the object AutomatedInstallData and its methods.
I'm programming in Visual C++ 2010. I've got a example.h example.cpp and Form1.h.
Basically, I've pasted bits of code. I'm not able to include Form1.h in the example.h file, not sure why. But The main question is how do I call Test (which is in form1.h) from example.cpp? What would be the syntax? Is it possible to do this?
My Form1.h
#include "example.h"
public ref class Form1 : public System::Windows::Forms::Form
{
public: void Test(void)
{
// Does something
}
}
My example.cpp
#include "example.h"
#include "Form1.h"
Test(); // would like to call Test from here.
You have two problems here:
You must call functions from inside of another function. The code you currently have in your example.cpp file is invalid, because you are trying to call the Test() function at global scope.
Make it look like this instead:
int main()
{
Test();
return 0;
}
This also solves the problem that you don't have a main function, which is the entry point to any C++ application.
More generally, I would strongly recommend using one of the project templates that comes with Visual Studio to get started (rather than copying and pasting random bits of code, like you said). That ensures that you have all of the things you need to get started, like an entry point. Once you have a solid foundation, you can start building up from there.
You might also find it useful to obtain either a book on C++/CLI or an online tutorial (such as this one: Hello C++/CLI, Part 1 and Hello C++/CLI, Part 2).
Your Test function is a member function of the Form1 class, which means that you need an object of that class in order to call it. Thus, the code should actually look like this:
int main()
{
Form1^ frm = gcnew Form1();
frm.Test();
return 0;
}
Alternatively, you could work around this by making the Test() function a static function. This would allow you to call it without having an instance of the class:
public ref class Form1 : public System::Windows::Forms::Form
{
public: static void Test(void)
{
// Does something
}
}
// ...
int main()
{
Form1::Test();
return 0;
}
However, beware that this means you cannot access any other members of the Form1 class inside of the Test() function (because there is no this pointer).
This should all be explained in whatever book/tutorial you decide to use to learn C++/CLI—search for a chapter about "Classes" or "Object-Oriented Design".
This is the class that implements Writable ..
public class Test implements Writable {
List<AtomicWritable> atoms = new ArrayList<AtomicWritable>();
public void write(DataOutput out) throws IOException {
IntWritable size = new IntWritable(atoms.size());
size.write(out);
for (AtomicWritable atom : atoms)
atom.write(out);
}
public void readFields(DataInput in) throws IOException {
atoms.clear();
IntWritable size = new IntWritable();
size.readFields(in);
int n = size.get();
while(n-- > 0) {
AtomicWritable atom = new AtomicWritable();
atom.readFields(in);
atoms.add(atom);
}
}
}
I will really appreciate if one can help me understand how to invoke write and readFields method.
Basically I m failing to understand how to construct Test object in this case. Once the object is written to DataOutput obj, how do we restore it in DataInput object. This may sound silly, but am a newbie to Hadoop and have been assigned a project that uses Hadoop. Please help.
Thanks!!!
Basically I m failing to understand how to construct Test object in this case.
Yup, you're missing the point. If you need to construct an instance of Test and populate atoms, then you need to add a constructor to Test:
public Test(ArrayList<AtomicWritable> atoms) {
this.atoms = atoms;
}
or you need to use the default constructor and add a method or a setter that lets you add items to atoms or set the value of atoms. The latter is actually pretty common in the Hadoop framework, to have a default constructor and a set method. cf., e.g., Text.set.
You don't call readFields and write; the Hadoop framework does that for you when it needs to serialize and deserialize inputs and outputs to and from map and reduce.
I've seen plenty of examples of calling static methods in my Unity C# code using C++. I haven't however seen any examples of how to call a single instance's method using C++. i.e rather than
public static void SomeMethod(
{
}
I really want to do:
public void SomeMethod()
{
}
I've managed to make the static implementation work by following some tutorials from but would love to know if the bottom method is possible. I've tried to add a definition for searching a method in a class.
MonoMethod* mono_method_desc_search_in_class (MonoMethodDesc *desc, MonoClass *klass);
But an implementation can't be found with the mono runtime that I was told to use from here: http://www.reigndesign.com/blog/unity-native-plugins-os-x/
Any guidance or knowledge of whether it's possible or how to do it would be appreciated.
Edit:
One other question. If I search for a gameObject, could I then use that to access the instance?
You don't say what platform you're developing for, but for iOS there's the UnitySendMessage function. I believe there are similar implementations for other platforms.
http://docs.unity3d.com/Documentation/Manual/PluginsForIOS.html
Calling C# / JavaScript back from native code
Unity iOS supports limited native-to-managed callback functionality via UnitySendMessage:
UnitySendMessage("GameObjectName1", "MethodName1", "Message to send");
The parameter must be a string, so I've used JSON to send more complex data.
Alternatively, everything that inherits from UnityEngine.Object has a GetInstanceID() method, which is guaranteed to be unique. Using this you could have a static method in C# that keeps a dictionary of recipient instances, and native code would always pass an integer ID to refer to the intended recipient.
static Dictionary<int, SomeClass> instanceDict = new Dictionary<...>();
void Awake() {
instanceDict.Add(GetInstanceID(), this);
}
void OnDestroy() {
instanceDict.Remove(GetInstanceID());
}
public static void SomeMethod(int recipientID, float someValue) {
instanceDict[recipientID].SomeMethod(someValue);
}
I have a C++/CLI class library project in VS2005 that i am having some problems with. I have defined a class called Languages which is a an enum class. which looks like this:
"Language.cpp"
namespace Company
{
namespace product
{
public eunm class Languages : int
{
English = 1,
German = 2,
//etc for other languages
};
}
};
I then have another class that tries to references this which lives in the same namespace:
"Language.cpp"
namespace Company
{
namespace product
{
public class LanguageConsumer
{
public:
LanguageConsumer()
{
}
public:
Languages DoSomething(Languages input)
{
if (input == Languages::English)
{
//Do something and return
}
};
}
};
However my project doensn't compile. From what i can figure out the different classes can't see each other even thought they are in the same namespace. I assume that i might need to have header files and #includes for the header files but i just don't know enough about C++/CLI to be sure (i come from C# background with hardly any C experience) and i have tried as many different combinations as i can think of. I'm sure i'm missing something very obvious to anybody who knows what they are doing, but alas i do not.
Thanks in advance.
C++/CLI still compiles like C++, file files are compiled separately and then linked together. This is different from C# which compiles all the files together. At compile time the files don't know about each other so the code doesn't compile (what is this enum?!). You need to have the enum definition in the same file (compilation unit) as the class.
The simple way to do this is to move the code into the same file. The header file solution is to move the enum definition into a header file and then include it (#include) in the other file. #include inserts the text of another file, giving the same effect.