Programming style
From Wikipedia, the free encyclopedia
Programming style refers to the style used in writing the source code for a computer program. Most programming styles are designed to help programmers quickly read and understand the program as well as avoid making errors. (Older programming styles also focused on conserving screen space.)
The programming style used in a particular program may be derived from the coding standards or code conventions of a company or other computing organization, as well as the preferences of the actual programmer. Programming styles are often designed for a specific programming language (or language family) and are not used in whole for other languages. ( Style considered good in C source code may not be appropriate for BASIC source code, and so on. )
Contents |
[edit] Elements of good style
Good style, being a subjective matter, is difficult to concretely categorize; however, there are several elements common to a large number of programming styles. Programming styles are often designed for a specific programming language and are not used in whole for other languages.
[edit] Code appearance
Programming styles commonly deal with the appearance of source code, with the goal of improving the readablity of the program. However, with the advent of software that formats source code automatically, the focus on appearance will likely yield to a greater focus on naming, logic, and higher techniques. As a practical point, using a computer to format source code saves time, and it is possible to then enforce company-wide standards without religious debates.
[edit] Indenting
Indent styles assist in identifying control flow and blocks of code. In programming languages that use indentation to delimits logical blocks of code, good intentation style directly affects the behavior of the resulting program. In other languages, such as those that use brackets to delimit code blocks, the indent style does not directly affect the product. Instead, using a logical and consistent indent style makes one's code more readable. Compare:
if(hours < 24 && minutes < 60 && seconds < 60){
return true;
}else{
return false;
}
or
if(hours < 24 && minutes < 60 && seconds < 60)
{
return true;
}
else
{
return false;
}
with something like
if(hours < 24 && minutes < 60 && seconds < 60) {return true;}
else{return false;}
The first two examples are much easier to read because they are indented well, and logical blocks of code are grouped and displayed together more clearly.
This example is somewhat contrived, of course - all the above are more complex (less stylish) than
return hours < 24 && minutes < 60 && seconds < 60;
[edit] Spacing
Free-format languages often completely ignore whitespace. Making good use of spacing in one's layout is therefore considered good programming style.
Compare the following examples of C code.
int count;
for(count=0;count<10;count++)
{
printf("%d",count*count+count);
}
with
int count;
for (count = 0; count < 10; count++)
{
printf("%d", count * count + count);
}
In the C-family languages, it is also recommended to avoid using tab characters in the middle of a line as different text editors render their width differently.
Python uses indentation to indicate control structures, so correct indentation is required. By doing this, the need for bracketing with curly braces ({ and }) is eliminated, and readability is improved while not interfering with common coding styles. However, this frequently leads to problems where code is copied and pasted into a Python program, requiring tedious reformatting. Additionally, Python code is rendered unusable when posted on a forum or webpage that removes whitespace.
[edit] Naming, Logic, and Higher Techniques
[edit] Appropriate variable names
Appropriate choices for variable names are seen as the keystone for good style. Poorly-named variables make code harder to read and understand.
For example, consider the following pseudocode snippet:
get a b c if a < 24 and b < 60 and c < 60 return true else return false
Because of the choice of variable names, the function of the code is difficult to work out. However, if the variable names are made more descriptive:
get hours minutes seconds if hours < 24 and minutes < 60 and seconds < 60 return true else return false
the code's intent is easier to discern, namely, "Given a 24-hour time, true will be returned if it is a valid time and false otherwise."
[edit] Boolean values in decision structures
Some programmers think decision structures such as the above, where the result of the decision is merely computation of a Boolean value, are overly verbose and even prone to error. They prefer to have the decision in the computation itself, like this:
return hours < 12 && minutes < 60 && seconds < 60;
The difference is often purely stylistic and syntactic, as modern compilers produce identical object code for both forms.
[edit] Looping and control structures
The use of logical control structures for looping adds to good programming style as well. It helps someone reading code to understand the program's sequence of execution (in imperative programming languages). For example, in pseudocode:
count = 0 while count < 5 print count * 2 count = count + 1 endwhile
The above snippet obeys the two aforementioned style guidelines, but the following use of the "for" construct makes the code much easier to read:
for count = 0, count < 5, count=count+1 print count * 2
In many languages, the often used "for each element in a range" pattern can be shortened to:
for count = 0 to 5 print count * 2
[edit] See also
[edit] External links
[edit] Coding conventions for languages
- Coding Standard: C# (Philips Medical Systems)
- Programming style for Mono
- Code Conventions for the Java Programming Language
- Ada 95 Quality and Style Guide: Guidelines for Professional Programmers
- Java Programming Style Guide
- Style Guide for Python Code
- Ambysoft's Coding Standards for Java
- PHP::PEAR Coding Standards
- Perl Style Guide
- Object Pascal Style Guide
[edit] Coding conventions for projects
- Mozilla Coding Style Guide
- Linux Kernel Coding Style (or Documentation/CodingStyle in the Linux Kernel source tree)
- The NetBSD source code style guide (formerly known as the BSD Kernel Normal Form)
