473,385 Members | 1,492 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,385 software developers and data experts.

& vs ptr

what is the difference between passing by & and passing by pointer
for example
doSomething(int & address);
doSomething(int * ptr);
thanks
Jul 22 '05 #1
1 5553
Steve wrote:
what is the difference between passing by & and passing by pointer
for example
doSomething(int & address);
Why "address"? A reference is not an address, it's an alias.
doSomething(int * ptr);


Basically the same difference as in declaring a reference versus
declaring a pointer

int main() {
double d;
double& rd = d;
double* pd = &d;
}

Performance-wise, they are often the same. Logically, they are,
because pointers can be null, references can't, so when I receive
an argument by address (a pointer by value), I need to test it for
being non-null before using. I don't have to do that with references.

Of course, the syntax is different for accessing the object. If you
have a reference, you just use its name to get to the object. If you
have a pointer you need to dereference it using the * operator. Also,
a reference like you described can only refer to a single object, but
a pointer could be the pointer to the first element of an array of
several objects and you may get to other elements of that array by
means of the indexing operator ([])...

Victor
Jul 22 '05 #2

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

9
by: Collin VanDyck | last post by:
I have a basic understanding of this, so forgive me if I am overly simplistic in my explanation of my problem.. I am trying to get a Java/Xalan transform to pass through a numeric character...
1
by: DrTebi | last post by:
Hello, I have the following problem: I used to "encode" my email address within links, in order to avoid (most) email spiders. So I had a link like this: <a...
0
by: Thomas Scheffler | last post by:
Hi, I runned in trouble using XALAN for XSL-Transformation. The following snipplet show what I mean: <a href="http://blah.com/?test=test&amp;test2=test2">Test1&amp;</a> <a...
4
by: Luklrc | last post by:
Hi, I'm having to create a querysting with javascript. My problem is that javscript turns the "&" characher into "&amp;" when it gets used as a querystring in the url EG: ...
4
by: johkar | last post by:
When the output method is set to xml, even though I have CDATA around my JavaScript, the operaters of && and < are converted to XML character entities which causes errors in my JavaScript. I know...
8
by: Nathan Sokalski | last post by:
I add a JavaScript event handler to some of my Webcontrols using the Attributes.Add() method as follows: Dim jscode as String = "return (event.keyCode>=65&&event.keyCode<=90);"...
11
by: Jeremy | last post by:
How can one stop a browser from converting &amp; to & ? We have a textarea in our system wehre a user can type in some html code and have it saved to the database. When the data is retireved...
14
by: Arne | last post by:
A lot of Firefox users I know, says they have problems with validation where the ampersand sign has to be written as &amp; to be valid. I don't have Firefox my self and don't wont to install it only...
12
by: InvalidLastName | last post by:
We have been used XslTransform. .NET 1.1, for transform XML document, Dataset with xsl to HTML. Some of these html contents contain javascript and links. For example: // javascript if (a &gt; b)...
7
by: John Nagle | last post by:
I've been parsing existing HTML with BeautifulSoup, and occasionally hit content which has something like "Design & Advertising", that is, an "&" instead of an "&amp;". Is there some way I can get...
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...
0
by: ryjfgjl | last post by:
In our work, we often need to import Excel data into databases (such as MySQL, SQL Server, Oracle) for data analysis and processing. Usually, we use database tools like Navicat or the Excel import...
0
by: taylorcarr | last post by:
A Canon printer is a smart device known for being advanced, efficient, and reliable. It is designed for home, office, and hybrid workspace use and can also be used for a variety of purposes. However,...
0
by: aa123db | last post by:
Variable and constants Use var or let for variables and const fror constants. Var foo ='bar'; Let foo ='bar';const baz ='bar'; Functions function $name$ ($parameters$) { } ...
0
by: ryjfgjl | last post by:
If we have dozens or hundreds of excel to import into the database, if we use the excel import function provided by database editors such as navicat, it will be extremely tedious and time-consuming...
0
BarryA
by: BarryA | last post by:
What are the essential steps and strategies outlined in the Data Structures and Algorithms (DSA) roadmap for aspiring data scientists? How can individuals effectively utilize this roadmap to progress...
1
by: nemocccc | last post by:
hello, everyone, I want to develop a software for my android phone for daily needs, any suggestions?
1
by: Sonnysonu | last post by:
This is the data of csv file 1 2 3 1 2 3 1 2 3 1 2 3 2 3 2 3 3 the lengths should be different i have to store the data by column-wise with in the specific length. suppose the i have to...
0
by: Hystou | last post by:
There are some requirements for setting up RAID: 1. The motherboard and BIOS support RAID configuration. 2. The motherboard has 2 or more available SATA protocol SSD/HDD slots (including MSATA, M.2...

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.