473,320 Members | 1,821 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,320 software developers and data experts.

wat is NAMESPACE

guys i need a clear explanation of namespace and why we are using it..
Oct 5 '06 #1
2 1710
tyreld
144 100+
Namespaces are used to prevent name collisions in the global scope. Using namespaces you can group logical code declarations like classes and functions under a useful name. Each of these names represents a sub-scope within the global scope. The following is a silly example showing two variables with the same name declared in different namespaces. Note that they are accesed by using their respective namespace name.

Expand|Select|Wrap|Line Numbers
  1. #include <iostream>
  2. using namespace std;
  3.  
  4. namespace first
  5. {
  6.   int var = 5;
  7. }
  8.  
  9. namespace second
  10. {
  11.   double var = 3.1416;
  12. }
  13.  
  14. int main () {
  15.   cout << first::var << endl;
  16.   cout << second::var << endl;
  17.   return 0;
  18. }
  19.  
Oct 5 '06 #2
Namespaces are used to prevent name collisions in the global scope. Using namespaces you can group logical code declarations like classes and functions under a useful name. Each of these names represents a sub-scope within the global scope. The following is a silly example showing two variables with the same name declared in different namespaces. Note that they are accesed by using their respective namespace name.

Expand|Select|Wrap|Line Numbers
  1. #include <iostream>
  2. using namespace std;
  3.  
  4. namespace first
  5. {
  6.   int var = 5;
  7. }
  8.  
  9. namespace second
  10. {
  11.   double var = 3.1416;
  12. }
  13.  
  14. int main () {
  15.   cout << first::var << endl;
  16.   cout << second::var << endl;
  17.   return 0;
  18. }
  19.  
thanks a lot..
Oct 5 '06 #3

Sign in to post your reply or Sign up for a free account.

Similar topics

1
by: John L. Clark | last post by:
I am curious as to the rationale, and effect, of having default namespaces not applying (directly) to attributes (see http://www.w3.org/TR/REC-xml-names/#defaulting). Given an attribute without a...
3
by: Mike Dickens | last post by:
hi, i'm sure this has come up before but havn't managed to find an answer. if i have the following xslt <?xml version="1.0" encoding="ISO-8859-1"?> <xsl:stylesheet method="xml" version="1.0"...
6
by: Don Wash | last post by:
Hi There! I just need some advice on Namespace management for creating reusable VB.NET applications. I would like my applications to have this namespace structure... Namespace MyCompany ...
8
by: Petter Reinholdtsen | last post by:
I ran into a problem on HP-UX 11.00 the other day, where it refused to compile a program using 'using namespace std;' at the top. The reason seem to be that the compiler refuses to accept 'using...
2
by: puzzlecracker | last post by:
after reading some of the post I found out something rather radical to my previous understanding: that when you do #include<iostream> #include<string> #include<vector> etc compiler puts...
2
by: Tony Johansson | last post by:
Hello! I'm reading a book about C++ and there is something that I don't understand so I ask you. Below I have the text from the book and the code from the file where main is located and some...
7
by: Kevin Newman | last post by:
I've been toying with a namespace manager, and wanted to get some input. So what do you think? if (typeof com == 'undefined') var com = {}; if (!com.unFocus) com.unFocus = {}; ...
14
by: Tiraman | last post by:
Hi , I would like to use nested namespace . I have 3 namespace as dll's : Namespace A Namespace B Namespace C And i want to have some namespace that contain them all , some thing like
2
by: Jeff Brown | last post by:
Hi, I suspect that this isn't possible, but I figured I'd ask. My project has a root namespace, let's say it's "Root", that applies to almost every source file (which is why I've set it as the...
0
by: DolphinDB | last post by:
Tired of spending countless mintues downsampling your data? Look no further! In this article, you’ll learn how to efficiently downsample 6.48 billion high-frequency records to 61 million...
0
isladogs
by: isladogs | last post by:
The next Access Europe meeting will be on Wednesday 6 Mar 2024 starting at 18:00 UK time (6PM UTC) and finishing at about 19:15 (7.15PM). In this month's session, we are pleased to welcome back...
0
by: Vimpel783 | last post by:
Hello! Guys, I found this code on the Internet, but I need to modify it a little. It works well, the problem is this: Data is sent from only one cell, in this case B5, but it is necessary that data...
0
by: ArrayDB | last post by:
The error message I've encountered is; ERROR:root:Error generating model response: exception: access violation writing 0x0000000000005140, which seems to be indicative of an access violation...
1
by: PapaRatzi | last post by:
Hello, I am teaching myself MS Access forms design and Visual Basic. I've created a table to capture a list of Top 30 singles and forms to capture new entries. The final step is a form (unbound)...
0
by: CloudSolutions | last post by:
Introduction: For many beginners and individual users, requiring a credit card and email registration may pose a barrier when starting to use cloud servers. However, some cloud server providers now...
0
by: Defcon1945 | last post by:
I'm trying to learn Python using Pycharm but import shutil doesn't work
0
by: af34tf | last post by:
Hi Guys, I have a domain whose name is BytesLimited.com, and I want to sell it. Does anyone know about platforms that allow me to list my domain in auction for free. Thank you
0
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 3 Apr 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 former...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.