&gt; The &quot;c&quot; stands for &quot;character&quot; because iostreams map values to and from byte (char) representations. [[Bjarne Stroustrup&#39;s C++ Style and Technique FAQ](http://www.stroustrup.com/bs_faq2.html#cout)]

I originally guessed ***console***, and [this link][1] confirmed it. But after seeing the [quote from Stroustrup][2], it seems that&#39;s a misconception, and that the c stands for **character**.

One thing in favor of that theory that can serve as an indicator is the fact that for each stream object (`cin`, `cout`, `cerr`, etc.) there is an equivalent, **wide-stream** one (`wcin`, `wcout`, `wcerr`, etc.).


  [1]: http://en.wikiversity.org/wiki/Introduction_to_C++#Console_in.2C_Console_out
  [2]: http://www.stroustrup.com/bs_faq2.html#cout

Edit: FredOverflow has found the right answer with a link toward Stroustrup web site.


A c++ standard draft (n1905.pdf on www.open-std.org, I don&#39;t have the exact link) seems to indicate that it comes from &quot;C&quot; : &quot;C standard output&quot; =&gt; cout

&gt; *27.3 Standard iostream objects [lib.iostream.objects]*
&gt; 
&gt; **1-  The header &amp;lt;iostream&gt; declares objects that associate
&gt; objects with the standard C streams
&gt; provided for by the functions declared
&gt; in &amp;lt;cstdio&gt; (27.8.2).**
&gt; 
&gt; [...]
&gt; 
&gt; 
&gt; *27.3.1 Narrow stream objects [lib.narrow.stream.objects]*
&gt; 
&gt; *istream cin*
&gt; 
&gt; **1-** The object cin controls input from a stream buffer associated with
&gt; the object stdin, declared in
&gt; &amp;lt;cstdio&gt;.
&gt;
&gt; [...]


The c stands for C, C++, and/or Character.

I have a DataTable that i want to convert it to xml and then zip it, using DotNetZip. finally user can download it via Asp.Net webpage.
My code in below 

        dt.TableName = &quot;Declaration&quot;;

        MemoryStream stream = new MemoryStream();
        dt.WriteXml(stream);

        ZipFile zipFile = new ZipFile();
        zipFile.AddEntry(&quot;Report.xml&quot;, &quot;&quot;, stream);
        Response.ClearContent();
        Response.ClearHeaders();
        Response.AppendHeader(&quot;content-disposition&quot;, &quot;attachment; filename=Report.zip&quot;);
       
        zipFile.Save(Response.OutputStream);
        //Response.Write(zipstream);
        zipFile.Dispose();

the xml file in zip file is empty.

Creating Zip file from stream and downloading it

I&#39;m trying to clear the `Entry` widget after the user presses a button using Tkinter. 

I tried using `ent.delete(0, END)`, but I got an error saying that strings don&#39;t have the attribute _delete_.

Here is my code, where I&#39;m getting error on `real.delete(0, END)`:

    secret = randrange(1,100)
    print(secret)
    def res(real, secret):
        if secret==eval(real):
            showinfo(message=&#39;that is right!&#39;)
        real.delete(0, END)
        
    def guess():
        ge = Tk()
        ge.title(&#39;guessing game&#39;)

        Label(ge, text=&quot;what is your guess:&quot;).pack(side=TOP)

        ent = Entry(ge)
        ent.pack(side=TOP)
 
        btn=Button(ge, text=&quot;Enter&quot;, command=lambda: res(ent.get(),secret))
        btn.pack(side=LEFT)

        ge.mainloop()


How to clear the Entry widget after a button is pressed in Tkinter?

What does the &quot;c&quot; mean in the `cout`, `cin`, `cerr` and `clog` names?

I would say `char` but I haven&#39;t found anything to confirm it.

What does the &quot;c&quot; mean in cout, cin, cerr and clog?

<p>What does the "c" mean in the <code>cout</code>, <code>cin</code>, <code>cerr</code> and <code>clog</code> names?</p>
<p>I would say <code>char</code> but I haven't found anything to confirm it.</p>


I&#39;m looking to create a hash with sha256 using openssl and C++. I know there&#39;s a similar post at [Generate SHA hash in C++ using OpenSSL library](https://stackoverflow.com/questions/918676/generate-sha-hash-in-openssl), but I&#39;m looking to specifically create sha256.

UPDATE: 

Seems to be a problem with the include paths. It can&#39;t find any OpenSSL functions even though I included 

    #include &quot;openssl/sha.h&quot;

and I included the paths in my build

    -I/opt/ssl/include/ -L/opt/ssl/lib/ -lcrypto 


Generate sha256 with OpenSSL and C++

Can anyone explain what they are and why I would need them? What kind of applications am I building if I need to use intrinsics?

What are intrinsics?

I want to define a constant in C++ to be visible in several source files.
I can imagine the following ways to define it in a header file:

 1. `#define GLOBAL_CONST_VAR 0xFF`
 2. `int GLOBAL_CONST_VAR = 0xFF;`
 3. Some function returing the value (e.g. `int get_GLOBAL_CONST_VAR()`)
 4. `enum { GLOBAL_CONST_VAR = 0xFF; }`
 5. `const int GLOBAL_CONST_VAR = 0xFF;`
 6. `extern const int GLOBAL_CONST_VAR;`
    and in one source file `const int GLOBAL_CONST_VAR = 0xFF;`

Option (1) - is definitely not the option you would like to use

Option (2) - defining instance of the variable in each object file using the header file

Option (3) - IMO is over killing in most cases

Option (4) - in many cases maybe not good since enum has no concrete type (C++0X will add possibility to define the type)
 
So in most cases I need to choose between (5) and (6).
My questions:

 1. What do you prefer (5) or (6)?
 2. Why (5) is ok, while (2)  is not?

Defining global constant in C++

Suppose I have a code like this:

    void printHex(std::ostream&amp; x){
        x&lt;&lt;std::hex&lt;&lt;123;
    }
    ..
    int main(){
        std::cout&lt;&lt;100; // prints 100 base 10
        printHex(std::cout); //prints 123 in hex
        std::cout&lt;&lt;73; //problem! prints 73 in hex..
    }
My question is if there is any way to &#39;restore&#39; the state of `cout` to its original one after returning from the function? (Somewhat like `std::boolalpha` and `std::noboolalpha`..) ?

Thanks.

Restore the state of std::cout after manipulating it

After a lot of investigations with valgrind, I&#39;ve made the conclusion that std::vector makes a copy of an object you want to push_back.

Is that really true ? A vector cannot keep a reference or a pointer of an object without a copy ?!

Thanks

Is std::vector copying the objects with a push_back?

Hi I was trying to output unicode string to a console with *iostreams* and failed.

I found this:  [Using unicode font in c++ console app][1]  and this snippet works.

    SetConsoleOutputCP(CP_UTF8);
    wchar_t s[] = L&quot;&#232;&#233;&#248;&#222;ǽлљΣ&#230;ča&quot;;
    int bufferSize = WideCharToMultiByte(CP_UTF8, 0, s, -1, NULL, 0, NULL, NULL);
    char* m = new char[bufferSize]; 
    WideCharToMultiByte(CP_UTF8, 0, s, -1, m, bufferSize, NULL, NULL);
    wprintf(L&quot;%S&quot;, m);

However, I did not find any way to output unicode correctly with iostreams. Any suggestions?

This does not work:

    SetConsoleOutputCP(CP_UTF8);
    utf8_locale = locale(old_locale,new boost::program_options::detail::utf8_codecvt_facet());
    wcout.imbue(utf8_locale);
    wcout &lt;&lt; L&quot;&#161;Hola!&quot; &lt;&lt; endl;

**EDIT**
I could not find any other solution than to wrap this snippet around in a stream.
Hope, somebody has better ideas.

    //Unicode output for a Windows console 
    ostream &amp;operator-(ostream &amp;stream, const wchar_t *s) 
    { 
    	int bufSize = WideCharToMultiByte(CP_UTF8, 0, s, -1, NULL, 0, NULL, NULL);
    	char *buf = new char[bufSize];
    	WideCharToMultiByte(CP_UTF8, 0, s, -1, buf, bufSize, NULL, NULL);
    	wprintf(L&quot;%S&quot;, buf);
    	delete[] buf; 
    	return stream; 
    } 
    
    ostream &amp;operator-(ostream &amp;stream, const wstring &amp;s) 
    { 
    	stream - s.c_str();
    	return stream; 
    } 

  [1]: https://stackoverflow.com/questions/1922294/using-unicode-font-in-c-console-app



Output unicode strings in Windows console app

First off, it may seem that I&#39;m asking for subjective opinions, but that&#39;s not what I&#39;m after. I&#39;d love to hear some well-grounded arguments on this topic.

---

**In the hope of getting some insight into how a modern streams / serialization framework ought to be designed,** I recently got myself a copy of the book [_Standard C++ IOStreams and Locales_ by Angelika Langer and Klaus Kreft](http://www.angelikalanger.com/iostreams.html). I figured that if IOStreams wasn&#39;t well-designed, it wouldn&#39;t have made it into the C++ standard library in the first place.

After having read various parts of this book, I am starting to have doubts if IOStreams can compare to e.g. the STL from an overall architectural point-of-view. Read e.g. [this interview with Alexander Stepanov (the STL&#39;s &quot;inventor&quot;)](http://www.stlport.org/resources/StepanovUSA.html) to learn about some design decisions that went into the STL.

**What surprises me in particular**:

* It seems to be unknown who was responsible for IOStreams&#39; overall design (I&#39;d love to read some background information about this &amp;mdash; does anyone know good resources?);

* Once you delve beneath the immediate surface of IOStreams, e.g. if you want to extend IOStreams with your own classes, you get to an interface with fairly cryptic and confusing member function names, e.g. `getloc`/`imbue`, `uflow`/`underflow`, `snextc`/`sbumpc`/`sgetc`/`sgetn`, `pbase`/`pptr`/`epptr` (and there&#39;s probably even worse examples). This makes it so much harder to understand the overall design and how the single parts co-operate. Even the book I mentioned above doesn&#39;t help _that_ much (IMHO).

---

**Thus my question:**

If you had to judge by today&#39;s software engineering standards (if there actually _is_ any general agreement on these), would C++&#39;s IOStreams still be considered well-designed? (I wouldn&#39;t want to improve my software design skills from something that&#39;s generally considered outdated.)

Who architected / designed C++&#39;s IOStreams, and would it still be considered well-designed by today&#39;s standards?

What is the difference between [`printf()`][1] and [`cout`][2] in C++?

  [1]: http://en.cppreference.com/w/cpp/io/c/fprintf
  [2]: http://en.cppreference.com/w/cpp/io/basic_ostream

&#39;printf&#39; vs. &#39;cout&#39; in C++

I&#39;m used to the Delphi VCL Framework, where TStreams throw exceptions on errors (e.g file not found, disk full). I&#39;m porting some code to use C++ STL instead, and have been caught out by iostreams NOT throwing exceptions by default, but setting [badbit/failbit flags][1] instead.

Two questions...

 a: Why is this - It seems an odd design decision for a language built with exceptions in it from day one?

 b: How best to avoid this? I could produce shim classes that throw as I would expect, but this feels like reinventing the wheel. Maybe there&#39;s a BOOST library that does this in a saner fashion?


  [1]: http://en.cppreference.com/w/cpp/io/ios_base/iostate

Why are C++ STL iostreams not &quot;exception friendly&quot;?

Is there a module for an [AVL tree](https://en.wikipedia.org/wiki/AVL_tree) or a [red–black tree](https://en.wikipedia.org/wiki/Red%E2%80%93black_tree) or some other type of a balanced binary tree in the standard library of Python?
 

Is there a module for balanced binary tree in Python&#39;s standard library?

Looking for a better way to get a machines current external IP #... Below works, but would rather not rely on an outside site to gather the information ... I am restricted to using standard Python 2.5.1 libraries bundled with Mac OS X 10.5.x

    import os
    import urllib2

    def check_in():

        fqn = os.uname()[1]
        ext_ip = urllib2.urlopen(&#39;http://whatismyip.org&#39;).read()
        print (&quot;Asset: %s &quot; % fqn, &quot;Checking in from IP#: %s &quot; % ext_ip)

Getting a machine&#39;s external IP address with Python

I feel like I must just be unable to find it. Is there any reason that the C++ `pow` function does not implement the &quot;power&quot; function for anything except `float`s and `double`s?

I know the implementation is trivial, I just feel like I&#39;m doing work that should be in a standard library. A robust power function (i.e. handles overflow in some consistent, explicit way) is not fun to write.

Why isn&#39;t `int pow(int base, int exponent)` in the standard C++ libraries?

I&#39;ve read on Stack Overflow that some C functions are &quot;obsolete&quot; or &quot;should be avoided&quot;. Can you please give me some examples of this kind of function and the reason why?

What alternatives to those functions exist?

Can we use them safely - any good practices?


Which functions from the standard library must (should) be avoided?

I need to read a whole file into memory and place it in a C++ `std::string`.

If I were to read it into a `char[]`, the answer would be very simple:

    std::ifstream t;
    int length;
    t.open(&quot;file.txt&quot;);      // open input file
    t.seekg(0, std::ios::end);    // go to the end
    length = t.tellg();           // report location (this is the length)
    t.seekg(0, std::ios::beg);    // go back to the beginning
    buffer = new char[length];    // allocate memory for a buffer of appropriate dimension
    t.read(buffer, length);       // read the whole file into the buffer
    t.close();                    // close file handle
    
    // ... Do stuff with buffer here ...

Now, I want to do the exact same thing, but using a `std::string` instead of a `char[]`. I want to avoid loops, i.e. I **don&#39;t** want to:

    std::ifstream t;
    t.open(&quot;file.txt&quot;);
    std::string buffer;
    std::string line;
    while(t){
    std::getline(t, line);
    // ... Append line to buffer and go on
    }
    t.close()

Any ideas?

Content Type	Original Author	Original Content on Stackoverflow
Question	Rexxar	View Question on Stackoverflow
Solution 1 - C++	fredoverflow	View Answer on Stackoverflow
Solution 2 - C++	JRL	View Answer on Stackoverflow
Solution 3 - C++	Rexxar	View Answer on Stackoverflow
Solution 4 - C++	Java1	View Answer on Stackoverflow

What does the "c" mean in cout, cin, cerr and clog?

C++ Problem Overview

C++ Solutions

Solution 1 - C++

Solution 2 - C++

Solution 3 - C++

Solution 4 - C++

How to clear the Entry widget after a button is pressed in Tkinter?

Creating Zip file from stream and downloading it

Attributions