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float length, width, height, price_gal_paint, total_area, total_cost;
int coverage_gal_paint, total_gal_paint;
However common this is in textbooks, it would generally not be acceptable to standards used in most companies. You should declare each item on its own line; like this:
float length;
float width;float height;
float price_gal_paint;int coverage_gal_paint;
float total_area;int total_gal_paint;
float total_cost;
This method of using one item per line is more readable by humans. It is quicker to find an identifier name, because you can read the list vertically faster than searching horizontally. Some programmers list them in alphabetic order, especially when the number of variables exceeds about twenty.
The lines of code inside either function are also aligned vertically and indented two spaces from the left. The indentation helps set the block off visually.
You can see through the source code short little comments that describe an area or section. Note the use of input, processing and output which are part of the IPO concept within the program design.
Note the use of comments in the form of a banner before each function.
//******************************************************
// main//******************************************************
The function name is placed with two lines of asterisks. It makes it extremely easy to find each function definition because you don’t have to read the functions to see where the one ends and the next one begins. You can quickly read the function names within the banners.
Within many languages there is a method to identify a group of programming statements as a unit. With C++ the functions use a set of symbols, the braces {}, to identify a block of code, sometimes referred to as a compound statement. Braces are used in other aspects of programs, but for now we will look at this simple example. These braces have a tendency to cause problems, especially when they don’t have a proper opening brace associated with a proper closing brace. To solve that problem many programmers simply put a brace on a line by itself and make sure the opening brace and closing brace are in the same vertical column.
A block of code associated with a function or with a control structure is indented two or three spaces. When blocks of code are nested each nesting is indented two or three spaces. In our example above the blocks of code for the function definitions are indented two spaces.
As the name implies "identifier names" should clearly identify who (or what) you are talking about. Calling you spouse "Snooky" may be meaningful to only you. Others might need to see her full name (Jane Mary Smith) to appropriately identify who you are talking about. The same concept in programming is true. Variables, constants, functions, typedefs and other items should use meaningful identifier names. Additionally, those names should be typed consistently in terms of upper and lower case as they are used in the program. Don't define a variable as: Pig and then type it later on in your program as: pig.
Many programming languages have a command that allows for the creation of an identifier name that represents a data type. The new identifier name is described or connected to a real data type. This feature is not demonstrated in the code above and is often a confusing concept. It is a powerful way to help document a program so that it is meaningful, but is often used by more experienced programmers.
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