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  • What does the destructor do silently?

    - by zhanwu
    Considering the following code which looks like that the destructor doesn't do any real job, valgrind showed me clearly that it has memory leak without using the destructor. Any body can explain me what does the destructor do in this case? #include <iostream> using namespace std; class A { private: int value; A* follower; public: A(int); ~A(); void insert(int); }; A::A(int n) { value = n; follower = NULL; } A::~A() { if (follower != NULL) delete follower; cout << "do nothing!" << endl; } void A::insert(int n) { if (this->follower == NULL) { A* f = new A(n); this->follower = f; } else this->follower->insert(n); } int main(int argc, char* argv[]) { A* objectA = new A(1); int i; for (i = 0; i < 10; i++) objectA->insert(i); delete objectA; }

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  • Create table class as a singleton

    - by Mark
    I got a class that I use as a table. This class got an array of 16 row classes. These row classes all have 6 double variables. The values of these rows are set once and never change. Would it be a good practice to make this table a singleton? The advantage is that it cost less memory, but the table will be called from multiple threads so I have to synchronize my code which way cause a bit slower application. However lookups in this table are probably a very small portion of the total code that is executed. EDIT: This is my code, are there better ways to do this or is this a good practice? Removed synchronized keyword according to recommendations in this question. final class HalfTimeTable { private HalfTimeRow[] table = new HalfTimeRow[16]; private static final HalfTimeTable instance = new HalfTimeTable(); private HalfTimeTable() { if (instance != null) { throw new IllegalStateException("Already instantiated"); } table[0] = new HalfTimeRow(4.0, 1.2599, 0.5050, 1.5, 1.7435, 0.1911); table[1] = new HalfTimeRow(8.0, 1.0000, 0.6514, 3.0, 1.3838, 0.4295); //etc } @Override @Deprecated public Object clone() throws CloneNotSupportedException { throw new CloneNotSupportedException(); } public static HalfTimeTable getInstance() { return instance; } public HalfTimeRow getRow(int rownumber) { return table[rownumber]; } }

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  • C/C++ Bit Array or Bit Vector

    - by MovieYoda
    Hi, I am learning C/C++ programming & have encountered the usage of 'Bit arrays' or 'Bit Vectors'. Am not able to understand their purpose? here are my doubts - Are they used as boolean flags? Can one use int arrays instead? (more memory of course, but..) What's this concept of Bit-Masking? If bit-masking is simple bit operations to get an appropriate flag, how do one program for them? is it not difficult to do this operation in head to see what the flag would be, as apposed to decimal numbers? I am looking for applications, so that I can understand better. for Eg - Q. You are given a file containing integers in the range (1 to 1 million). There are some duplicates and hence some numbers are missing. Find the fastest way of finding missing numbers? For the above question, I have read solutions telling me to use bit arrays. How would one store each integer in a bit?

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  • How to get results efficiently out of an Octree/Quadtree?

    - by Reveazure
    I am working on a piece of 3D software that has sometimes has to perform intersections between massive numbers of curves (sometimes ~100,000). The most natural way to do this is to do an N^2 bounding box check, and then those curves whose bounding boxes overlap get intersected. I heard good things about octrees, so I decided to try implementing one to see if I would get improved performance. Here's my design: Each octree node is implemented as a class with a list of subnodes and an ordered list of object indices. When an object is being added, it's added to the lowest node that entirely contains the object, or some of that node's children if the object doesn't fill all of the children. Now, what I want to do is retrieve all objects that share a tree node with a given object. To do this, I traverse all tree nodes, and if they contain the given index, I add all of their other indices to an ordered list. This is efficient because the indices within each node are already ordered, so finding out if each index is already in the list is fast. However, the list ends up having to be resized, and this takes up most of the time in the algorithm. So what I need is some kind of tree-like data structure that will allow me to efficiently add ordered data, and also be efficient in memory. Any suggestions?

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  • Is `super` local variable?

    - by Michael
    // A : Parent @implementation A -(id) init { // change self here then return it } @end A A *a = [[A alloc] init]; a. Just wondering, if self is a local variable or global? If it's local then what is the point of self = [super init] in init? I can successfully define some local variable and use like this, why would I need to assign it to self. -(id) init { id tmp = [super init]; if(tmp != nil) { //do stuff } return tmp; } b. If [super init] returns some other object instance and I have to overwrite self then I will not be able to access A's methods any more, since it will be completely new object? Am I right? c. super and self pointing to the same memory and the major difference between them is method lookup order. Am I right? sorry, don't have Mac to try, learning theory as for now...

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  • How can I use io.StringIO() with the csv module?

    - by Tim Pietzcker
    I tried to backport a Python 3 program to 2.7, and I'm stuck with a strange problem: >>> import io >>> import csv >>> output = io.StringIO() >>> output.write("Hello!") # Fail: io.StringIO expects Unicode Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: unicode argument expected, got 'str' >>> output.write(u"Hello!") # This works as expected. 6L >>> writer = csv.writer(output) # Now let's try this with the csv module: >>> csvdata = [u"Hello", u"Goodbye"] # Look ma, all Unicode! (?) >>> writer.writerow(csvdata) # Sadly, no. Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: unicode argument expected, got 'str' According to the docs, io.StringIO() returns an in-memory stream for Unicode text. It works correctly when I try and feed it a Unicode string manually. Why does it fail in conjunction with the csv module, even if all the strings being written are Unicode strings? Where does the str come from that causes the Exception? (I do know that I can use StringIO.StringIO() instead, but I'm wondering what's wrong with io.StringIO() in this scenario)

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  • How can I get sessions to work if I'm using Google App Engine + Django 1.1?

    - by user341642
    Is there a way for me to get sessions working? I know Django has built in session management, and GAE has some tools for it if you're using their watered down version of Django 0.96, but is there a way to get sessions to work if you're trying to use GAE w/ Django 1.1 (i.e. use_library() call). I assume using a db-backed session doesn't work, and a file system backed one won't work b/c we don't have access to the filesystem if we deploy to the Google production servers. This kinda worked (as in didn't crap out) when I used SessionMiddleware backed by a local-memory backed cache and a non-persistent cache (i.e. setting SESSION_ENGINE to django.contrib.sessions.backends.cache). But the session never seems to persist in this case, no matter how I set the timeouts. A new session key is generated on every page reload. Maybe this is b/c the GAE assumes complete statelessness with each request and blows away my local cache? Apologies in advance, I'm pretty new to Python. Any suggestions would be greatly appreciated.

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  • HTML5 Local Storage of audio element source - is it possible?

    - by andrewdotcom
    Hi stackoverflow experts I've been experimenting with the audio and local storage features of html5 of late and have run into something that has me stumped. I'd like to be able to cache or store the source of the audio element locally to enable speedier and offline playback. The problem is I can't see how this is possible with the current implementation. I have tried the following using webkit: Creating a manifest file to set up local caching but the audio file appears not to be a cacheable item maybe due to the way it is stream or something I have also attempted to use javascript to put an audio object into local storage but the size of the mp3 makes this impossible due to memory issues (i think). I have tried to use the data uri and base64 to use the html as a audio transport that can be cached but again the filesize makes this prohibitive. Also the audio element does not seem to like this in webkit (works fine in mozilla) I have tried several methods of putting the data into the local database store. Again suffering the same issues as the other cases. I'd love to hear any other ideas anyone may have as to how I could achieve my goal of offline playback using caching/local storage in webkit.

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  • What does the Asterisk * mean in Objective-C?

    - by Thanks
    Is it true, that the Asterisk always means "Hey, that is a pointer!" And an Pointer always holds an memory adress? (Yes I know for the exception that a * is used for math operation) For Example: NSString* myString; or SomeClass* thatClass; or (*somePointerToAStruct).myStructComponent = 5; I feel that there is more I need to know about the Asterirsk (*) than that I use it when defining an Variable that is a pointer to a class. Because sometimes I already say in the declaration of an parameter that the Parameter variable is a pointer, and still I have to use the Asterisk in front of the Variable in order to access the value. That recently happened after I wanted to pass a pointer of an struct to a method in a way like [myObj myMethod:&myStruct], I could not access a component value from that structure even though my method declaration already said that there is a parameter (DemoStruct*)myVar which indeed should be already known as a pointer to that demostruct, still I had always to say: "Man, compiler. Listen! It IIISSS a pointer:" and write: (*myVar).myStructComponentX = 5; I really really really do not understand why I have to say that twice. And only in this case. When I use the Asterisk in context of an NSString* myString then I can just access myString however I like, without telling the compiler each time that it's a pointer. i.e. like using *myString = @"yep". It just makes no sense to me.

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  • Strategy for animation a lot of LED's - thread?, UIView animations? NSOperation? (iPhone)

    - by RickiG
    Hi I have to do some different views containing 72 LED lights. I built an LED Class so I can loop through the LED's and set them to different colors (Green, Red, Orange, Blue None etc.). The LED then loads the appropriate .png. This works fine, I loop over the LED's and set them. Now I know that at some time they will need to not just turn on/off change color, but will have to turn on with a small delay. Like an equalizer. I have a 5-10 views containing the 72 LED's and I would like to achieve the above with the minimum amount of memory/CPU strain. for(LED *l in self.ledArray) { [l display:Green]; } I simply loop as shown above and inside the LED is a switch case that does the correct logic. If this were actual LED's and a microController I would use sleep(100) or similar in the loop, but I would really like to avoid stuff like that for obvious reasons. I was thinking that doing a performOnThread withDelay would really be consuming, so would UIView animation changing the alpha and NSOperation would also be a lot of lifting for a small feature. Is there a both efficient and clever way to go around this? Thanks for any inspiration given:)

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  • Good C string libary

    - by chamakits
    Hello all. I recently got inspired to start up a project I've been wanting to code for a while. I want to do it in C, because memory handling is key this application. I was searching around for a good implementation of strings in C, since I know me doing it myself could lead to some messy buffer overflows, and I expect to be dealing with a fairly big amount of strings. I found this article which gives details on each, but they each seem like they have a good amount of cons going for them (don't get me wrong, this article is EXTREMELY helpful, but it still worries me that even if I were to choose one of those, I wouldn't be using the best I can get). I also don't know how up to date the article is, hence my current plea. What I'm looking for is something that may hold a large amount of characters, and simplifies the process of searching through the string. If it allows me to tokenize the string in any way, even better. Also, it should have some pretty good I/O performance. Printing, and formatted printing isn't quite a top priority. I know I shouldn't expect a library to do all the work for me, but was just wandering if there was a well documented string function out there that could save me some time and some work. Any help is greatly appreciated. Thanks in advance! EDIT: I was asked about the license I prefer. Any sort of open source license will do, but preferably GPL (v2 or v3). EDIt2: I found betterString (bstring) library and it looks pretty good. Good documentation, small yet versatile amount of functions, and easy to mix with c strings. Anyone have any good or bad stories about it? The only downside I've read about it is that it lacks Unicode (again, read about this, haven't seen it face to face just yet), but everything else seems pretty good. EDIT3: Also, preferable that its pure C.

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  • float** allocation limit + serialized struct problem. Need advice!

    - by jmgunn
    basically im getting an allocation limit error/warning when i create a float** array. the function i am calling to fill the float** retrieves data from a struct loaded from a file. The function works fine when i use one object but when i load 2 objects into memory i get the limit error. I am pretty sure this is to do with byte alignment or a similar thing because my struct is saved with a float** member which i am sure you are not susposed to do !?! Please confirm this! The next question i have now is how to save/serialize the float** member of this struct? I cant really afford to put an upper bound on the array ie "float [10000][3]" because i need/want to use this structure as a base for many other types of objects that may have well under the upper bound. Stroking my chin here! Any help/advice will recieve my highest gratitude. BTW these said struct objects will be used in a game/graphics package, the float** is a float[3] array for storing vertices in a model. Much thanks in advance

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  • Pointers to a typed variable in C#: Interfase, Generic, object or Class? (Boxing/Unboxing)

    - by PaulG
    First of all, I apologize if this has been asked a thousand times. I read my C# book, I googled it, but I can't seem to find the answer I am looking for, or I am missing the point big time. I am very confused with the whole boxing/unboxing issue. Say I have fields of different classes, all returning typed variables (e.g. 'double') and I would like to have a variable point to any of these fields. In plain old C I would do something like: double * newVar; newVar = &oldVar; newVar = &anotherVar; ... In C#, it seems I could do an interfase, but would require that all fields be properties and named the same. Breaks apart when one of the properties doesn't have the same name or is not a property. I could also create a generic class returning double, but seems a bit absurd to create a class to represent a 'double', when a 'double' class already exists. If I am not mistaken, it doesn't even need to be generic, could be a simple class returning double. I could create an object and box the typed variable to the newly created object, but then I would have to cast every time I use it. Of course, I always have the unsafe option... but afraid of getting to unknown memory space, divide by zero and bring an end to this world. None of these seem to be the same as the old simple 'double * variable'. Am I missing something here?

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  • What is the best way to properly test object equality against an array of objects?

    - by radesix
    My objective is to abort the NSXMLParser when I parse an item that already exists in cache. The basic flow of the program works like this: 1) Program starts and downloads an XML feed. Each item in the feed is represented by a custom object (FeedItem). Each FeedItem gets added to an array. 2) When the parsing is complete the contents of the array (all FeedItem objects) are archived to the disk. The next time the program is executed or the feed is refreshed by the user I begin parsing again; however, since a cache (array) now exists as each item is parsed I want to see if the object exists in the cache. If it does then I know I have downloaded all the new items and no longer need to continue parsing. What I am learning, I think, is that I can't use indexOfObject or indexOfObjectIDenticalTo: because these really seem to be checking to see that the objects are using the same memory address (thus identical). What I want to do is see if the contents of the object are equal (or at least some of the contents). I've done some research and found that I can override the IsEqual method; however, I really don't want to iterate/enumerate through the entire cache contents table for every newly parsed XML FeedItem. Is iterating through the collection and testing each one for equality the only way to do this or is there a better technique I am not aware of? Currently I am using the following code though I know it needs to change: NSUInteger index = [self.feedListCache.feedList indexOfObject:self.currentFeedItem]; if (index == NSNotFound) { }

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  • base class , inheritate class sizeof()

    - by user1279988
    why sizeof(X) is 4 and sizeof(Y) is 8? and another question, in class X, only the int(i) count as sizeof() 4? member function does take any memory space? Plz tell me, thanks! class X { int i; public: X() { i = 0; } void set(int ii) { i = ii; } int read() const { return i; } int permute() { return i = i * 47; } }; class Y : public X { int i; // Different from X's i public: Y() { i = 0; } int change() { i = permute(); // Different name call return i; } void set(int ii) { i = ii; X::set(ii); // Same-name function call } }; cout << "sizeof(X) = " << sizeof(X) << endl; cout << "sizeof(Y) = "

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  • Strange code behaviour?

    - by goldenmean
    Hi, I have a C code in which i have a structure declaration which has an array of int[576] declared in it. For some reason, i had to remove this array from the structure, So i replaced this array with a pointer as int *ptr; declared some global array of same type, somewhere else in the code, and initialized this pointer by assigning the global array to this pointer. So i did not have to change the way i was accessing this array, from other parts of my code. But it works fine/gives desired output when i have the array declared in the structure, but it gives junk output when i declare it as a pointer in the structure and assign a global array to this pointer, as a part of the pointer initialization. All this code is being run on MS-VC 6.0/Windows setup/Intel-x86. I tried below things: 1)Suspected structure padding/alignment but could not get any leads? If at all structure alignment could be a culprit how can i proceed to narrow it down and confirm it? 2) I have made sure that in both cases the array is initialized to some default values, say 0 before its first use, and its not being used before initialization. 3)I tried using global array as well as malloc based memory for this newly declared array. Same result, junk output. Am i missing something? How can i zero down the problem. Any pointers would be helpful. Thanks, -AD.

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  • How to current snapshot of MySQL Table and store it into CSV file(after creating it) ?

    - by Rachel
    I have large database table, approximately 5GB, now I wan to getCurrentSnapshot of Database using "Select * from MyTableName", am using PDO in PHP to interact with Database. So preparing a query and then executing it // Execute the prepared query $result->execute(); $resultCollection = $result->fetchAll(PDO::FETCH_ASSOC); is not an efficient way as lots of memory is being user for storing into the associative array data which is approximately, 5GB. My final goal is to collect data returned by Select query into an CSV file and put CSV file at an FTP Location from where Client can get it. Other Option I thought was to do: SELECT * INTO OUTFILE "c:/mydata.csv" FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"' LINES TERMINATED BY "\n" FROM my_table; But I am not sure if this would work as I have cron that initiates the complete process and we do not have an csv file, so basically for this approach, PHP Scripts will have to create an CSV file. Do a Select query on the database. Store the select query result into the CSV file. What would be the best or efficient way to do this kind of task ? Any Suggestions !!!

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  • Variable Scoping in a method and its persistence in C++

    - by de costo
    Consider the following public method that adds an integer variable to a vector of ints(private member) in a class in C++. KoolMethod() { int x; x = 10; KoolList.Add(x); } Vector<int>KoolList; But is this a valid addition to a vector ??? Upon calling the method, it creates a local variable. The scope of this local variable ends the moment the execution control leaves the method. And since this local variable is allocated on a stack(on the method call), any member of KoolList points to an invalid memory location in deallocated stack which may or may not contain the expected value of x. Is this an accurate description of above mechanism ?? Is there a need for creating an int in heap storage using "new" operator everytime a value needs to be added to the vector like described below ????: KoolMethod() { int *x = new int(); *x = 10; KoolList.Add(x); } Vector<int*>KoolList;

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  • Rails Nested Attributes Doesn't Insert ID Correctly

    - by MunkiPhD
    I'm attempting to edit a model's nested attributes, much as outline here, replicated here: <%= form_for @person do |person_form| %> <%= person_form.text_field :name %> <% for address in @person.addresses %> <%= person_form.fields_for address, :index => address do |address_form|%> <%= address_form.text_field :city %> <% end %> <% end %> <% end %> In my code, I have the following: <%= form_for(@meal) do |f| %> <!-- some other stuff that's irrelevant... --> <% for subitem in @meal.meal_line_items %> <%= f.fields_for subitem, :index => subitem do |line_item_form| %> <%= line_item_form.label :servings %><br/> <%= line_item_form.text_field :servings %><br/> <%= line_item_form.label :food_id %><br/> <%= line_item_form.text_field :food_id %><br/> <% end %> <% end %> <%= f.submit %> <% end %> This works great, except, when I look at the HTML, it's creating the inputs that look like the following, failing to input the correct id and instead placing the memory representation(?) of the model: <input type="text" value="2" size="30" name="meal[meal_line_item][#<MealLineItem:0x00000005c5d618>][servings]" id="meal_meal_line_item_#<MealLineItem:0x00000005c5d618>_servings">

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  • Calling member functions dynamically

    - by user652511
    I'm pretty sure it's possible to call a class and its member function dynamically in Delphi, but I can't quite seem to make it work. What am I missing? // Here's a list of classes (some code removed for clarity) moClassList : TList; moClassList.Add( TClassA ); moClassList.Add( TClassB ); // Here is where I want to call an object's member function if the // object's class is in the list: for i := 0 to moClassList.Count - 1 do if oObject is TClass(moClassList[i]) then with oObject as TClass(moClassList[i]) do Foo(); I get an undeclared identifier for Foo() at compile. Clarification/Additional Information: What I'm trying to accomplish is to create a Change Notification system between business classes. Class A registers to be notified of changes in Class B, and the system stores a mapping of Class A - Class B. Then, when a Class B object changes, the system will call a A.Foo() to process the change. I'd like the notification system to not require any hard-coded classes if possible. There will always be a Foo() for any class that registers for notification. Maybe this can't be done or there's a completely different and better approach to my problem. By the way, this is not exactly an "Observer" design pattern because it's not dealing with objects in memory. Managing changes between related persistent data seems like a standard problem to be solved, but I've not found very much discussion about it. Again, any assistance would be greatly appreciated. Jeff

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  • Vacancy Tracking Algorithm implementation in C++

    - by Dave
    I'm trying to use the vacancy tracking algorithm to perform transposition of multidimensional arrays in C++. The arrays come as void pointers so I'm using address manipulation to perform the copies. Basically, there is an algorithm that starts with an offset and works its way through the whole 1-d representation of the array like swiss cheese, knocking out other offsets until it gets back to the original one. Then, you have to start at the next, untouched offset and do it again. You repeat until all offsets have been touched. Right now, I'm using a std::set to just fill up all possible offsets (0 up to the multiplicative fold of the dimensions of the array). Then, as I go through the algorithm, I erase from the set. I figure this would be fastest because I need to randomly access offsets in the tree/set and delete them. Then I need to quickly find the next untouched/undeleted offset. First of all, filling up the set is very slow and it seems like there must be a better way. It's individually calling new[] for every insert. So if I have 5 million offsets, there's 5 million news, plus re-balancing the tree constantly which as you know is not fast for a pre-sorted list. Second, deleting is slow as well. Third, assuming 4-byte data types like int and float, I'm using up actually the same amount of memory as the array itself to store this list of untouched offsets. Fourth, determining if there are any untouched offsets and getting one of them is fast -- a good thing. Does anyone have suggestions for any of these issues?

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  • The cross-thread usage of "HttpContext.Current" property and related things

    - by smwikipedia
    I read from < Essential ASP.NET with Examples in C# the following statement: Another useful property to know about is the static Current property of the HttpContext class. This property always points to the current instance of the HttpContext class for the request being serviced. This can be convenient if you are writing helper classes that will be used from pages or other pipeline classes and may need to access the context for whatever reason. By using the static Current property to retrieve the context, you can avoid passing a reference to it to helper classes. For example, the class shown in Listing 4-1 uses the Current property of the context to access the QueryString and print something to the current response buffer. Note that for this static property to be correctly initialized, the caller must be executing on the original request thread, so if you have spawned additional threads to perform work during a request, you must take care to provide access to the context class yourself. I am wondering about the root cause of the bold part, and one thing leads to another, here is my thoughts: We know that a process can have multiple threads. Each of these threads have their own stacks, respectively. These threads also have access to a shared memory area, the heap. The stack then, as I understand it, is kind of where all the context for that thread is stored. For a thread to access something in the heap it must use a pointer, and the pointer is stored on its stack. So when we make some cross-thread calls, we must make sure that all the necessary context info is passed from the caller thread's stack to the callee thread's stack. But I am not quite sure if I made any mistake. Any comments will be deeply appreciated. Thanks. ADD Here the stack is limited to user stack.

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  • Calculating with a variable outside of its bounds in C

    - by aquanar
    If I make a calculation with a variable where an intermediate part of the calculation goes higher then the bounds of that variable type, is there any hazard that some platforms may not like? This is an example of what I'm asking: int a, b; a=30000; b=(a*32000)/32767; I have compiled this, and it does give the correct answer of 29297 (well, within truncating error, anyway). But the part that worries me is that 30,000*32,000 = 960,000,000, which is a 30-bit number, and thus cannot be stored in a 16-bit int. The end result is well within the bounds of an int, but I was expecting that whatever working part of memory would have the same size allocated as the largest source variables did, so an overflow error would occur. This is just a small example to show my problem, I am trying to avoid using floating points by making the fraction be a fraction of the max amount able to be stored in that variable (in this case, a signed integer, so 32767 on the positive side), because the embedded system I'm using I believe does not have an FPU. So how do most processors handle calculations out of the bounds of the source and destination variables?

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  • std::thread and class constructor and destructor

    - by toeplitz
    When testing threads in C++11 I have created the following example: #include <iostream> #include <thread> class Foo { public: Foo(void) { std::cout << "Constructor called: " << this << std::endl; } ~Foo(void) { std::cout << "Destructor called: " << this << std::endl; } void operator()() const { std::cout << "Operatior called: " << this << std::endl; } }; void test_normal(void) { std::cout << "====> Standard example:" << std::endl; Foo f; } void test_thread(void) { std::cout << "====> Thread example:" << std::endl; Foo f; std::thread t(f); t.detach(); } int main(int argc, char **argv) { test_normal(); test_thread(); for(;;); } Which prints the following: Why is the destructor called 6 times for the thread? And why does the thread report different memory locations?

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  • I just don't get the C++ Pointer/Reference system.

    - by gnm
    I've never had problems with references as in Python (implicit) or PHP (explicit &). In PHP you write $p = &$myvar; and you have $p as a reference pointing to $myVar. So I know in C++ you can do this: void setToSomething( int& var ) { var = 123; } int myInt; setToSomething( myInt ); Myint is now 123, why? Doesn't & mean "memory address of" x in C++? What do I do then if var is only the adress to myInt and not a pointer? void setToSomething( int* var ) { var* = 123; } int myInt; int* myIntPtr = &myInt; setToSomething( myIntPtr ); Does the above work as expected? I don't understand the difference between * and & in C++ fully. They tell you & is used to get the adress of a variable, but why IN GODS NAME does that help you in functions etc. like in the first example?

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