No, it doesn&#39;t. It has *pointers*, but they&#39;re not quite the same thing.

In particular, all arguments in C are passed by value, rather than pass-by-reference being available as in C++. Of course, you can sort of *simulate* pass-by-reference via pointers:

    void foo(int *x)
    {
        *x = 10;
    }

    ...

    int y = 0;
    foo(&amp;y); // Pass the pointer by value
    // The value of y is now 10

For more details about the differences between pointers and references, see [this SO question][1]. (And please don&#39;t ask me, as I&#39;m not a C or C++ programmer :)


  [1]: https://stackoverflow.com/questions/57483/difference-between-pointer-variable-and-reference-variable-in-c

Conceptually, C has references, since pointers reference other objects. 

Syntactically, C does not have references as C++ does. 

I have a service that gets a JPA entity from outside code. In this service I would like to iterate over a lazily loaded collection that is an attribute of this entity to see if the client has added something to it relative to the current version in the DB.

However, the client may have never touched the collection so it&#39;s still not initialized. This results in the well known 

`org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.example.SomeEntity.`

Of course, if the client never touched the collection, my service doesn&#39;t have to check it for possible changes. The thing is that I can&#39;t seem to find a way to test whether the collection is initialized or not. I guess I could call `size()` on it and if it throws `LazyInitializationException` I would know, but I&#39;m trying not to depend on such patterns.

Is there some `isInitialized()` method somewhere?

How to test whether lazy loaded JPA collection is initialized?

I&#39;d like to check if there are any `.rar` files in a directory. It doesn’t need to be recursive.

Using wildcard with `os.path.isfile()` was my best guess, but it doesn&#39;t work. What can I do then?

Use wildcard with os.path.isfile()

Does C have references? i.e. as in C++ :

    void foo(int &amp;i)

Does C have references?

Does C have references? i.e. as in C++ :
<pre><code class="hljs language-java">void foo(int &#x26;i)
</code></pre>

Consider:

    struct mystruct_A
    {
       char a;
       int b;
       char c;
    } x;

    struct mystruct_B
    {
       int b;
       char a;
    } y;

The sizes of the structures are 12 and 8 respectively.

Are these structures padded or packed?

When does padding or packing take place?


Structure padding and packing

I am working with C and I&#39;m a bit rusty.  I am aware that `*` has three uses:

1. Declaring a pointer.
2. Dereferencing a pointer.
3. Multiplication

However, what does it mean when there are two asterisks (`**`) before a variable declaration:

    char **aPointer = ...

Thanks,

Scott

In C, what does a variable declaration with two asterisks (**) mean?

**How can I set a breakpoint in C or C++ code programatically that will work for gdb on Linux?**

*I.e.:*

    int main(int argc, char** argv)
    {
        /* set breakpoint here! */
        int a = 3;
        a++;  /*  In gdb&gt; print a;  expect result to be 3 */
        return 0;
    }



Set breakpoint in C or C++ code programmatically for gdb on Linux

So I know that the difference between a `signed int` and `unsigned int` is that a bit is used to signify if the number if positive or negative, but how does this apply to a `char`? How can a character be positive or negative?

Difference between signed / unsigned char

I am currently reading the book C Programming Language by Ritchie &amp; Kernighan. And I am pretty confused about the usage of EOF in the `getchar()` function. 

First, I want to know why the value of EOF is -1 and why the value of `getchar()!=EOF` is 0. Pardon me for my question but I really don&#39;t understand. I really tried but I can&#39;t. 

Then I tried to run the example on the book that can count the number of characters using the code below but it seems that I never get out of the loop even if I press enter so I am wondering when would I reach the EOF?

    main(){
       long nc;
       nc = 0;
       while (getchar() != EOF)
           ++nc;
       printf(&quot;%ld\n&quot;, nc);
    }

Then, I read the same problem at [https://stackoverflow.com/questions/1622092/problem-with-eof-in-c][1]. Most people advised that instead of using EOF, use the terminator \n or the null terminator &#39;\0&#39; which makes a lot of sense.

Does it mean that the example on the book serves another purpose? 


  [1]: https://stackoverflow.com/questions/1622092/problem-with-eof-in-c

End of File (EOF) in C

I keep getting the same issue over and over again where an object I want to reference is copied or where an object I want to copy is referenced. This happens when I use the = operator.

For example, if I am sending the object to another form, ie: 

    SomeForm myForm = new SomeForm();
    SomeObject myObject = new SomeObject();
    myForm.formObject = myObject;

...and then modify the object in the form, the original object does not get modified. It is as if the object was copied and not referenced. Yet, when I do this:

    SomeObject myObject = new SomeObject();
    SomeObject anotherObject = new SomeObject();
    anotherObject = myObject;

...and then modify `anotherObject`, `myObject` gets modified as well.

The most aggravating case is when I try to Clone one of my defined objects:

    public class SomeObject
    {
        double value1, value2;
    
        //default constructor here
    
        public SomeObject(val1, val2)
        {
            value1 = val1;
            value2 = val2;
        }
    
        public void Clone(SomeObject thingToCopy)
        {
            this.value1 = thingToCopy.value1;
            this.value2 = thingToCopy.value2;
        }
    }

when I do this...

    SomeObject obj1 = new SomeObject(1, 2);
    SomeObject obj2 = new SomeObject();
    obj2.Clone(obj1);

...`obj1` is referenced and any modifications to `obj2` changes `obj1`.

System objects such as &lt;code&gt;int, double, string&lt;/code&gt;, etc seem to always be copied, except for in the case of the clone method above.

My question is, not taking into account the use of the &lt;code&gt;ref&lt;/code&gt; keyword in functions, when does an object get copied and when does an object get referenced in every case of the matter (i.e. when passing to functions, when setting as other objects (like the first two above examples), when copying member variables like the third example, etc.)?

When is a C# value/object copied and when is its reference copied?

Is this piece of code valid (and defined behavior)?

    int &amp;nullReference = *(int*)0;

Both g++ and clang++ compile it without any warning, even when using `-Wall`, `-Wextra`, `-std=c++98`, `-pedantic`, `-Weffc++`...

Of course the reference is not actually null, since it cannot be accessed (it would mean dereferencing a null pointer), but we could check whether it&#39;s null or not by checking its address:

    if( &amp; nullReference == 0 ) // null reference

Is null reference possible?

I&#39;m having another of these &quot;Could not load file or assembly or one of its dependencies&quot; problems.

&gt; Additional information: Could not load
&gt; file or assembly
&gt; &#39;Microsoft.Practices.Unity,
&gt; Version=1.2.0.0, Culture=neutral,
&gt; PublicKeyToken=31bf3856ad364e35&#39; or
&gt; one of its dependencies. The located
&gt; assembly&#39;s manifest definition does
&gt; not match the assembly reference.
&gt; (Exception from HRESULT: 0x80131040)

I have no idea what is causing this or how I could debug it to find the cause.

I&#39;ve done a search in my solution catalogs .csproj files, and every where I have Unity I have:

&gt; Reference
&gt; Include=&quot;Microsoft.Practices.Unity,
&gt; Version=2.0.414.0, Culture=neutral,
&gt; PublicKeyToken=31bf3856ad364e35,
&gt; processorArchitecture=MSIL&quot;

Can&#39;t find any reference anywhere which goes against 1.2.0.0 in any of my projects.

Any ideas how I should go about solving this?

Could not load file or assembly or one of its dependencies

I&#39;ve noticed that I usually use constant references as return values or arguments. I think the reason is that it works almost the same as using non-reference in the code. But it definitely takes more space and function declarations become longer. I&#39;m OK with such code but I think some people my find it a bad programming style.

What do you think? Is it worth writing *const int&amp;* over *int*? I think it&#39;s optimized by the compiler anyway, so maybe I&#39;m just wasting my time coding it, a?

int vs const int&amp;

I have a `C#` solution with several projects in `Visual Studio 2010`.
One is a test project (I&#39;ll call it &quot;*PrjTest*&quot;), the other is a `Windows Forms Application` project (I&#39;ll call it &quot;*PrjForm*&quot;).  There is also a third project referenced by PrjForm, which it is able to reference and use successfully.

*PrjForm* references *PrjTest*, and *PrjForm* has a class with a `using` statement:

    using PrjTest;

1. Reference has been correctly added
2. `using` statement is correctly in place
3. Spelling is correct
4. PrjTest builds successfully
5. PrjForm almost builds, but breaks on the `using PrjTest;` line with the error:

***The type or namespace name &#39;PrjTest&#39; could not be found (are you missing a using directive or an assembly reference?)***

I&#39;ve tried the following to resolve this:

1. Removed Resharper (since Resharper had no trouble recognizing the referenced project, I thought it might be worth a shot) 
2. Removed and re-added the reference and using statement
3. Recreated PrjForm from scratch
4. PrjForm currently resides inside the PrjTest folder, I tried moving it to an outside folder
5. Loaded the solution on a different computer with a fresh copy of `VS 2010`

I have done my homework and spent far too long looking for an answer online, none of the solutions has helped yet.

What else could I try?

Content Type	Original Author	Original Content on Stackoverflow
Question	jacky jack	View Question on Stackoverflow
Solution 1 - C	Jon Skeet	View Answer on Stackoverflow
Solution 2 - C	sbi	View Answer on Stackoverflow

Does C have references?

C Problem Overview

C Solutions

Solution 1 - C

Solution 2 - C

Use wildcard with os.path.isfile()

How to test whether lazy loaded JPA collection is initialized?

Attributions