CString member explanation

Question

0.00/5 (No votes)

See more:

Can someone explain to me exactly what the ASSERT is all about?

C#

Example
 // First example demonstrating
// CString::Find ( TCHAR ch )
CString s( "abcdef" );
ASSERT( s.Find( 'c' ) == 2 );
ASSERT( s.Find( "de" ) == 3 );

Thanks
-DrB

Posted 22-Dec-11 16:28pm

DrBones69

Add a Solution

Comments

Albert Holguin 23-Dec-11 5:40am

First thing you need to understand, ASSERT is not a CString member, it's a macro. So if you want to understand what it's doing, you probably need to understand macros first.

4 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Maximilien · Accepted Answer · 2011-12-22T17:04:00

the ASSERT will test the argument and report if the argument is false.

In your particular example (the msdn example of CString::Find), the ASSERT will be triggered if the result of CString::Find is not what is expected.

in the first instance, the result is and must be 2 ( c is at position 2 (zero based) in the string; if the result is something else, then the ASSERT will be triggered and a warning will be posted to the user.

It should be noted that ASSERTs will only be executed in DEBUG mode, meaning that the code in the argument will not be executed; most of the time it is not a big issue because we test the RESULT of the expression, not the expression itself :

C++

CString s( "abcdef" );
bool result = s.Find( 'c' ) == 2;
ASSERT(result);

Sergey Alexandrovich Kryukov · Accepted Answer · 2011-12-22T18:25:00

DrBones69 wrote:

Why would I or anyone ever need this? I am researching how to find substrings in a CString and came across this.

Assertion is a widely used fundamental concept of computer science and practical development methods.

See:
http://en.wikipedia.org/wiki/Assertion_(computing)[^]
http://en.wikipedia.org/wiki/Assertion_%28computing%29#Usage[^], as well as the articles references at the end of this page.

I clearly remember the time when I first came across this concept in C++ and immediately saw the importance of this little tools. If someone doubt its value, this looks so unusual, so it looks difficult to explain "why". Even though it is explained in detail in the article referenced above, please pay attention at the section "Assertions during the development cycle". It is important to understand that the usual use of assertions is related to the support of the project, not to the functionality of its release. Most common practice is to make assertions compiled conditionally, so the are skipped in release configuration. In this case, the role of assertions is to fail run-time test in debug configuration, when the condition of the assertion is not held.

—SA

KingsGambit · Accepted Answer · 2011-12-22T16:44:00

Solution 1

Following MSDN link explains it:
http://msdn.microsoft.com/en-us/library/ew16s3zc%28v=VS.100%29.aspx[^].

Posted 22-Dec-11 16:44pm

KingsGambit

Updated 22-Dec-11 18:28pm

v2

Comments

DrBones69 23-Dec-11 0:01am

Thanks, I read this, but I don't see any need for it. What is a good use for it?

Sergey Alexandrovich Kryukov 23-Dec-11 0:26am

Not obvious? Well, I tried to explain it in my answer, please see.
--SA

Sergey Alexandrovich Kryukov 23-Dec-11 0:30am

I cannot agree with the vote of 3. What OP needs is to read this help page. So I counter-voted with my 5.
Also, I've replaced your link by a later one, would you mind?
I also added the explanation in my answer in response to OP's question, please see.
--SA

Chuck O'Toole · Accepted Answer · 2011-12-23T01:49:00

It is quite common in documentation that includes examples of a functions usage to use ASSERT in the example in leiu of using words.

For example, your post:

C#

Example
 // First example demonstrating
// CString::Find ( TCHAR ch )
CString s( "abcdef" );
ASSERT( s.Find( 'c' ) == 2 );
ASSERT( s.Find( "de" ) == 3 );

Is really saying:

C#

Example
 // First example demonstrating
// CString::Find ( TCHAR ch )
CString s( "abcdef" );
//
// s.Find( 'c' ); will return the value 2 
// s.Find( "de" ); will return the value 3

Microsoft does this all the time. It's just showing the specific results of a specific usage with known inputs.

CString member explanation

4 solutions

Solution 2

Solution 3

Solution 1

Solution 4

Add your solution here

Preview 0