c# generating barcode CROSS-REFERENCE in Visual C#

Painting European Article Number 13 in Visual C# CROSS-REFERENCE

7 CROSS-REFERENCE
Creating European Article Number 13 In Visual C#
Using Barcode encoder for VS .NET Control to generate, create UPC - 13 image in VS .NET applications.
www.OnBarcode.com
Recognizing UPC - 13 In Visual C#
Using Barcode decoder for .NET framework Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
8 e-level performance optimi-
Generating Bar Code In C#.NET
Using Barcode creation for Visual Studio .NET Control to generate, create bar code image in VS .NET applications.
www.OnBarcode.com
Barcode Recognizer In C#.NET
Using Barcode scanner for .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
zations are discussed in 25, Code-Tuning 0 Strategies, and 26, 1 Code-Tuning Techniques.
EAN-13 Generation In .NET
Using Barcode maker for ASP.NET Control to generate, create EAN / UCC - 13 image in ASP.NET applications.
www.OnBarcode.com
Paint EAN 13 In Visual Studio .NET
Using Barcode maker for Visual Studio .NET Control to generate, create GTIN - 13 image in VS .NET applications.
www.OnBarcode.com
In C++, avoid using multiple operations per line (side effects) Side effects are consequences of a statement other than its main consequence. In C++, the ++ operator on a line that contains other operations is a side effect. Likewise, assigning a value to a variable and using the left side of the assignment in a conditional is a side effect.
EAN13 Generator In VB.NET
Using Barcode drawer for VS .NET Control to generate, create GS1 - 13 image in Visual Studio .NET applications.
www.OnBarcode.com
Make EAN13 In Visual C#.NET
Using Barcode creation for Visual Studio .NET Control to generate, create GTIN - 13 image in Visual Studio .NET applications.
www.OnBarcode.com
Side effects tend to make code difficult to read. For example, if n equals 4, what is the printout of the statement shown in Listing 31-46
2D Barcode Creator In C#.NET
Using Barcode printer for Visual Studio .NET Control to generate, create 2D Barcode image in VS .NET applications.
www.OnBarcode.com
Making Barcode In C#.NET
Using Barcode drawer for .NET Control to generate, create bar code image in .NET applications.
www.OnBarcode.com
Listing 31-46. C++ example of an unpredictable side effect.
Code 3 Of 9 Drawer In C#
Using Barcode creator for VS .NET Control to generate, create Code 39 image in .NET framework applications.
www.OnBarcode.com
Draw Uniform Symbology Specification Codabar In Visual C#
Using Barcode printer for .NET Control to generate, create Code 2 of 7 image in Visual Studio .NET applications.
www.OnBarcode.com
PrintMessage( ++n, n + 2 );
Creating GS1 DataBar Limited In Java
Using Barcode drawer for Java Control to generate, create GS1 DataBar Stacked image in Java applications.
www.OnBarcode.com
Create UPC-A In Java
Using Barcode generation for Java Control to generate, create GS1 - 12 image in Java applications.
www.OnBarcode.com
Is it 4 and 6 Is it 5 and 7 Is it 5 and 6 The answer is None of the above. The first argument, ++n, is 5. But the C++ language does not define the order in which terms in an expression or arguments to a routine are evaluated. So the compiler can evaluate the second argument, n + 2, either before or after the first argument; the result might be either 6 or 7, depending on the compiler. Listing 31-47 shows how you should rewrite the statement so that the intent is clear:
Paint ANSI/AIM Code 39 In None
Using Barcode maker for Software Control to generate, create ANSI/AIM Code 39 image in Software applications.
www.OnBarcode.com
EAN13 Reader In VB.NET
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
de Complete
UPC Code Decoder In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
UPCA Generation In None
Using Barcode creator for Font Control to generate, create UCC - 12 image in Font applications.
www.OnBarcode.com
31. Layout and Style
Print QR Code JIS X 0510 In Objective-C
Using Barcode printer for iPad Control to generate, create QR Code image in iPad applications.
www.OnBarcode.com
Encoding ECC200 In Java
Using Barcode creation for Java Control to generate, create Data Matrix image in Java applications.
www.OnBarcode.com
Page 33
Listing 31-47. C++ example of avoiding an unpredictable side effect.
++n; PrintMessage( n, n + 2 );
If you re still not convinced that you should put side effects on lines by themselves, try to figure out what the routine shown in Listing 31-48 does:
Listing 31-48. C example of too many operations on a line.
strcpy( char * t, char * s ) { while ( *++t = *++s ) ; }
Some experienced C programmers don t see the complexity in that example because it s a familiar function; they look at it and say, That s strcpy(). In this case, however, it s not quite strcpy(). It contains an error. If you said, That s strcpy() when you saw the code, you were recognizing the code, not reading it. This is exactly the situation you re in when you debug a program: The code that you overlook because you recognize it rather than read it can contain the error that s harder to find than it needs to be. The fragment shown in Listing 31-49 is functionally identical to the first and is more readable:
Listing 31-49. C example of a readable number of operations on each line.
strcpy( char * t, char * s ) { do { ++t; ++s; *t = *s; } while ( *t != '\0' ); }
In the reformatted code, the error is apparent. Clearly, t and s are incremented before *s is copied to *t. The first character is missed. The second example looks more elaborate than the first, even though the operations performed in the second example are identical. The reason it looks more elaborate is that it doesn t hide the complexity of the operations.
5 CROSS-REFERENCE
6 details on code tuning, see
25, Code-Tuning Strategies, and 26, 8 Code-Tuning Techniques.
Improved performance doesn t justify putting multiple operations on the same line either. Because the two strcpy() routines are logically equivalent, you would expect the compiler to generate identical code for them. When both versions of the routine were profiled, however, the first version took 4.81 seconds to copy 5,000,000 strings and the second took 4.35 seconds.
de Complete
31. Layout and Style
Page 34
In this case, the clever version carries an 11 percent speed penalty, which makes it look a lot less clever. The results vary from compiler to compiler, but in general they suggest that until you ve measured performance gains, you re better off striving for clarity and correctness first, performance second. Even if you read statements with side effects easily, take pity on other people who will read your code. Most good programmers need to think twice to understand expressions with side effects. Let them use their brain cells to understand the larger questions of how your code works rather than the syntactic details of a specific expression.
Copyright © OnBarcode.com . All rights reserved.