some function make the data type of it's parameters as "const char*"
why not use char or char* instead
what would be different 4 8390
Virtual_X wrote:
some function make the data type of it's parameters as "const char*"
why not use char or char* instead
what would be different
The type 'char' can only help passing a _single_ character.
The type 'char*' can help passing an array of non-constant characters.
The type 'const char*' helps passing an array of constant characters.
It means the function needs an array (often it's a C-string), and the
function promises that it will not change the contents of the array.
V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask
Victor Bazarov wrote:
Virtual_X wrote:
>some function make the data type of it's parameters as "const char*"
why not use char or char* instead what would be different
The type 'char' can only help passing a _single_ character.
The type 'char*' can help passing an array of non-constant characters.
The type 'const char*' helps passing an array of constant characters.
It means the function needs an array (often it's a C-string),
Even though it usually does need one for the case of pointers to char, the
declaration doesn't mean that. The function gets a pointer to a single
char. It's just a convention between the function and the caller that this
actually points to the first element of an array.
A function which parameter is const char *, it can accept char * and
const char * type of argument.
But if function's parameter is only char *, it will give a compilation
error when you try to
pass a const char *.
On Jul 12, 11:30 pm, Rolf Magnus <ramag...@t-online.dewrote:
Victor Bazarov wrote:
Virtual_X wrote:
some function make the data type of it's parameters as "const char*"
why not use char or char* instead
what would be different
The type 'char' can only help passing a _single_ character.
The type 'char*' can help passing an array of non-constant characters.
The type 'const char*' helps passing an array of constant characters.
It means the function needs an array (often it's a C-string),
Even though it usually does need one for the case of pointers to char, the
declaration doesn't mean that. The function gets a pointer to a single
char. It's just a convention between the function and the caller that this
actually points to the first element of an array.
su************* ***@gmail.com wrote:
A function which parameter is const char *, it can accept char * and
const char * type of argument.
Please don't top-post. Your replies belong following or interspersed
with properly trimmed quotes. See the majority of other posts in the
newsgroup, or the group FAQ list:
<http://www.parashift.c om/c++-faq-lite/how-to-post.html> This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: s88 |
last post by:
Hi all:
I saw the code likes...
7 #include <stdio.h>
8 int main(void){
9 const char *const green = "\033[0;40;32m";
10 const char *const normal = "\033[0m";
11 printf("%sHello World%s\n", green, normal);
12 return 0;
13 }
|
by: C. J. Clegg |
last post by:
A month or so ago I read a discussion about putting const ints in
header files, and how one shouldn't put things in header files that
allocate memory, etc. because they will generate multiple definition
errors if the header file is #include'd in more than one code file.
The answer was that constants have internal linkage unless declared
extern, so it's OK.
So, you can put something like...
|
by: Gary |
last post by:
Hi all! I've taken some time on learning the difference between
"pointers to const variables" and "const pointer variables". The
question is: in the following code, can we change the contents of the
const pointer (i.e. t)? I got a segmentation fault in the last for
loop.
I wrote the code in c++, but the language is not the point, right? :)
Thanks in advance!
#include <iostream>
|
by: =?gb2312?B?wNbA1rTzzOzKpg==?= |
last post by:
i wrote:
-----------------------------------------------------------------------
----------------------------------------
unsigned char * p = reinterpret_cast<unsigned char *>("abcdg");
sizeof(reinterpret_cast<const char *>(p));
-----------------------------------------------------------------------
----------------------------------------
the compiler tells me that "reinterpret_cast from type "const char * "
to type "unsigned char *"...
|
by: liujiaping |
last post by:
I'm confused about the program below:
int
main(int argc, char* argv)
{
char str1 = "abc";
char str2 = "abc";
const char str3 = "abc";
const char str4 = "abc";
const char* str5 = "abc";
| |
by: Darin Johnson |
last post by:
I keep running across that I'm maintaining that likes to define
function parameters as "const char &" or "const int &", etc.
Ie, constant reference parameters to a primitive type. This is
for normal functions, not operators.
I keep changing these to just have the plain old type, which
is more efficient (I'm using embedded systems) and less
obtuse. I'm puzzled why this one programmer insisted on
odd style everywhere. Maybe he's just...
|
by: W Marsh |
last post by:
Hi,
Could anybody tell me wh the parameter "T val" is not marked const in
this Stroustrup code, considering that val is not modified and not non-
const methods called?
template<class C, class Tint count(const C&v, T val)
{
typename C::const_iterator i = find(v.begin(), v.end(), val);
int n = 0;
|
by: Luna Moon |
last post by:
Hi all,
I just couldn't get myself clear about the usage of "const" in front
of and/or behind variables, pointers, classes, objects and
functions...
It's too confusing... any good clear article/tutorial that can help
me?
Thanks a lot!
|
by: Bill Davy |
last post by:
I want to be able to write (const char*)v where v is an item of type
Class::ToolTypeT where ToolTypeT is an enumeration and I've tried
everything that looks sensible. There's an ugly solution, but surely this is
possible?
I could define an operator<< but for various reasons, I really want to
convert to a 'const char*' (to embed into a string which becomes part of a
window's caption, etc).
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
|
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
The Art of Business Website Design
Your website is...
| |
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
|
by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules.
He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms.
Adolph will...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
|
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
| |
by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...
| |