These data types were added in C99.  Since `bool` wasn&#39;t reserved prior to C99, they use the `_Bool` keyword (which was reserved).

`bool` is an alias for `_Bool` if you include `stdbool.h`. Basically, including the `stdbool.h` header is an indication that your code is OK with the identifier `bool` being &#39;reserved&#39;, i.e. that your code won&#39;t use it for its own purposes (similarly for the identifiers `true` and `false`).



There is no difference.

`bool` is a macro that expands to `_Bool` in `stdbool.h`.

And `true` is a macro that expands to 1 in `stdbool.h`

I have a `books` table with a `returned_date` column. I&#39;d like to see the results for all of the books with a returned date that occurred in the past week.

Any thoughts? I tried doing some date math, but Postgres wasn&#39;t happy with my attempt.

How do you find results that occurred in the past week?

I am trying to do some comparison logic about the positions of HTML elements. I have a system that I think should work, but there is a problem. 

In my code I compare the current left and top values of one absolutely positioned element to those of another (which may be moving) using inequality statements (`&gt;` and `&lt;`).  The problem is that the feedback I get form `document.getElementById(nameVar).style.left` is in the form of a string (e.g. `200px`) not a number (e.g. `200`), so the comparisons don&#39;t work.

My question is, is there any way to turn the string into a number that I can manipulate the way I want to?  Either by using an altered address or by preforming some procedure with the feedback once I get it.

Any help would be great.

Get a number for a style value WITHOUT the &quot;px;&quot; suffix

Can anyone explain me what is the difference between the `_Bool` and `bool` data type in C?

For example:

     _Bool x = 1;
      bool y = true;
    
      printf(&quot;%d&quot;, x);
      printf(&quot;%d&quot;, y);


Difference between _Bool and bool types in C?

Can anyone explain me what is the difference between the <code>_Bool</code> and <code>bool</code> data type in C?
For example:
<pre><code class="hljs language-ini"> _Bool x = 1;
 bool y = true;

 printf("%d", x);
 printf("%d", y);
</code></pre>

I am wondering what is the maximum number of characters for a host-name in a Unix system. In addition is there any defined variable that can be used in Unix programming to call that number? (i.e. number of characters allowed for a host-name).

I am programming in C.

What is the maximum number of characters for a host-name in Unix?

Can anyone explain me what is a difference between these lines of code

    char *p = &quot;String&quot;;
    char p2[] = &quot;String&quot;;
    char p3[7] = &quot;String&quot;;

In what case should I use each of the above ?

How to declare strings in C

following excerpted from [here][1]

&gt;     pw = (widget *)malloc(sizeof(widget));
&gt; 
&gt; allocates raw storage. Indeed, the malloc call allocates storage
&gt; that&#39;s big enough and **suitably aligned to hold an object** of type
&gt; widget

also see [fast pImpl][2] from herb sutter, he said:

&gt; *Alignment*. Any memory Alignment. Any memory that&#39;s allocated
&gt; dynamically **via new or malloc is guaranteed to be properly aligned** for
&gt; objects of any type, but buffers that are not allocated dynamically
&gt; have no such guarantee

I am curious about this, how does malloc know alignment of the custom type?

  [1]: http://drdobbs.com/cpp/232200120
  [2]: http://www.gotw.ca/publications/mill05.htm

how does malloc understand alignment?

&gt; **Possible Duplicate:**  
&gt; [How to implement getch() function of C in Linux?](https://stackoverflow.com/questions/3276546/how-to-implement-getch-function-of-c-in-linux)  

&lt;!-- End of automatically inserted text --&gt;

What is the equivalent `Linux` version of the `conio.h` header file from MS-DOS?

Is there a way to replace its functionality? *e.g. `getch()`*

&gt; I&#39;m using `gcc` and the text editor `Geany` to compile `C` code.



Where is the &lt;conio.h&gt; header file on Linux? Why can&#39;t I find &lt;conio.h&gt;?

Well, I can&#39;t understand when and why it is needed to allocate memory using `malloc`.

Here is my code :

    #include &lt;stdlib.h&gt;
    
    int main(int argc, const char *argv[]) {
    
      typedef struct {
        char *name;
        char *sex;
        int age;
      } student;
    
    
      //Now I can do two things
      student p;
    
      //or
      student *ptr = (student *)malloc(sizeof(student));
    
      return 0;
    }

Why is it needed to allocate memory when I can just use `student p;`?

When and why to use malloc?

Sometime I stumble into the semi-mysterious notation of 

    def f[T](..) = new T[({type l[A]=SomeType[A,..]})#l] {..} 

in Scala blog posts, which give it a &quot;we used that type-lambda trick&quot; handwave.

While I have some intutition about this (we gain an anonymous type parameter `A` without having to pollute the definition with it?), I found no clear source describing what the type lambda trick is, and what are its benefits. Is it just syntactic sugar, or does it open some new dimensions?



What are type lambdas in Scala and what are their benefits?

This is a past exam question and I was wondering what a primitive type and reference type are first off?
With an array I know the a reference type is where the array is composed of objects or variables, but a primitive type is where you would create the array with just int or strings. (right?)

How do you think you would answer the question on the test and be given good credit? Without really referring directly to an primitive ARRAY type... Is there a way to do it without that? Or do you think it would be fine to just explain it with the array.

What&#39;s the difference between primitive and reference types?

I have a method which returns different types of instances (classes):

    public [What Here?] GetAnything()
    {
         Hello hello = new Hello();
         Computer computer = new Computer();
         Radio radio = new Radio();

         return radio; or return computer; or return hello //should be possible?!      
    }



How can I do this and later work with the variables, e.g. `radio.Play()`, etc? 

Do I need to use generics, and if so, how?

C# Return different types?

I have:

    DataTable Table = new DataTable;
    SqlConnection = new System.Data.SqlClient.SqlConnection(&quot;Data Source=&quot; + ServerName + &quot;;Initial Catalog=&quot; + DatabaseName + &quot;;Integrated Security=SSPI; Connect Timeout=120&quot;);

    SqlDataAdapter adapter = new SqlDataAdapter(&quot;Select * from &quot; + TableName, Connection);
    adapter.FillSchema(Table, SchemaType.Source);
    adapter.Fill(Table);

    DataColumn column = DataTable.Columns[0];

What I want to do is:

**Assume currently *column.DataType.Name* is *&quot;Double&quot;*. I want it to become *&quot;Int32&quot;*.**

How do I achieve this?

How To Change DataType of a DataColumn in a DataTable?

I am sending file from client to server using TCP. To mark the end of the file I like to send file size before the actual data. So I use `stat` system call to find the size of the file. This is of type `off_t`. I like to know how many bytes it occupies so that I can read it properly on the server side. It is defined in the  `&lt;sys/types.h&gt;`. But I do not understand the definition. It just defines `__off_t or _off64_t` to be `off_t`. Where to look for `__off_t`? Also is it convention that `__` is prefixed for most of the things in header files and scares me when I read header files to understand better. How to read a header file better?

    #ifndef __off_t_defined
    # ifndef __USE_FILE_OFFSET64
    typedef __off_t off_t;
    # else
    typedef __off64_t off_t;
    # endif
    # define __off_t_defined
    #endif 

Where to find the complete definition of off_t type?

A question mostly for fun/curiosity: how to write a `for` loop in C++ that would iterate over two values of a `bool` (i.e. `true` and `false`), using only operations with `bool` (i.e. without conversions to other types)?

The background is that I wanted to check how many solutions exists for an equation like `(A &amp;&amp; B) || (!B &amp;&amp; !C &amp;&amp; !D) == true`, and started to write something like `for (bool A=false; ??? ; ++A) for (bool B=false; ...)` etc but immediately got stuck by `???` - i.e. what would be the condition to continue the loop? Of course I rewrote it to use int, and I also know that a `do ... while` loop will work, but I got curious if it&#39;s ever possible to write such a `for` loop? And since SO does not seem to have an answer, I decided to ask :)

-----
Update: note that an &quot;obvious&quot; variant `for(bool A=false; !A; A=true)` suggested in at least two now-removed answers will only run one iteration, because for the second one the condition `!A` becomes `false` and the loop ends.

After some pondering, I believe it&#39;s impossible to do it in C++03 without a second variable or a pointer based construct like suggested by Dietmar K&#252;hl. The condition should be tested three times in a desired execution, so two values of a bool are simply not enough. And the do-while loop works because the first iteration is executed unconditionally, the condition is only checked twice and so a bool value can be used to select between continuing and exiting.

How to write a `for` loop over bool values (false and true)

I need to create a **Java** method to return `true` or `false` randomly. How can I do this?

Return True or False Randomly

I am programming in Objective-C for iOS. I would like to parse an object of type NSString into a scalar of type BOOL.

I have a value, and I know that it will either be @&quot;YES&quot; or @&quot;NO&quot;, but that YES (or) NO value is NSString and I just want to change NSString into BOOL.

How can I do that?

Please answer me if you know.

Thanks for reading.

How to parse NSString into BOOL in Objective-C?

I have some checks to see if a screen is active. The code looks like this:

    if (GUI.Button(new Rect(Screen.width / 2 - 10, 50, 50, 30), &quot;Rules&quot;)) //Creates a button
    	{
    		if (ruleScreenActive == true) //check if the screen is already active
    			ruleScreenActive = false; //handle according to that
    		else 
    			ruleScreenActive = true;
    	}

Is there any way to - whenever I click the button - invert the value of `ruleScreenActive`?

(This is C# in Unity3D)

Can I &#39;invert&#39; a bool?

I was wondering if it was possible to do a ternary operation but without returning anything.

If it&#39;s not possible in Java is it possible in other languages, if so which ones apply?



    
    name.isChecked() ? name.setChecked(true):name.setChecked(false);

Content Type	Original Author	Original Content on Stackoverflow
Question	pr1m3x	View Question on Stackoverflow
Solution 1 - C	Michael Burr	View Answer on Stackoverflow
Solution 2 - C	ouah	View Answer on Stackoverflow

Difference between _Bool and bool types in C?

C Problem Overview

C Solutions

Solution 1 - C

Solution 2 - C

Get a number for a style value WITHOUT the "px;" suffix

How do you find results that occurred in the past week?

Attributions