Coding with Style

Stylistic Challenges

Many programmers begin a new project by pledging that, this time, they will do everything right. Any time a variable or parameter shouldn’t be changed, it’ll be marked const. All variables will have clear, concise, readable names. Every developer will put the left curly brace on the subsequent line and will adopt the standard text editor and its conventions for tabs and spaces.

For a number of reasons, it is difficult to sustain this level of stylistic consistency. In the case of const, sometimes programmers just aren’t educated about how to use it. You will eventually come across old code or a library function that isn’t const-savvy. A good programmer will use const_cast to temporarily suspend the const property of a variable but an inexperienced programmer will start to unwind the const property back from the calling function, once again ending up with a program that never uses const.

Other times, standardization of style comes up against programmers’ own individual tastes and biases. Perhaps the culture of your team makes it impractical to enforce strict style guidelines. In such situations, you may have to decide which elements you really need to standardize (such as variable names and tabs) and which ones are safe to leave up to individuals (perhaps spacing and commenting style). You can even obtain or write scripts that will automatically correct style “bugs” or flag stylistic problems along with code errors.

Summar y

The C++ language provides a number of stylistic tools without any formal guidelines for how to use them. Ultimately, any style convention is measured by how widely it is adopted and how much it benefits the readability of the code. When coding as part of a team, you should raise issues of style early in the process as part of the discussion of what language and tools to use.

The most important point about style is to appreciate that it is an important aspect of programming. Teach yourself to check over the style of your code before you make it available to others. Recognize good style in the code you interact with and adopt the conventions that you and your organization find useful.

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Gaining Proficiency with Classes and Objects

As an object-oriented language, C++ provides facilities for using objects and for writing object definitions, called classes. You can certainly write programs in C++ without classes and objects, but by doing so, you do not take advantage of the most fundamental and useful aspect of the language; writing a C++ program without classes is like traveling to Paris and eating at McDonald’s! In order to use classes and objects effectively, you must understand their syntax and capabilities.

Chapter 1 reviewed the basic syntax of class definitions. Chapter 3 introduced the object-oriented approach to programming in C++ and presented specific design strategies for classes and objects. This chapter describes the fundamental concepts involved in using classes and objects, including writing class definitions, defining methods, using objects on the stack and the heap, writing constructors, default constructors, compiler-generated constructors, initializer lists in constructors, copy constructors, destructors, and assignment operators. Even if you are already comfortable with classes and objects, you should skim this chapter because it contains various tidbits of information with which you might not yet be familiar.

Introducing the Spreadsheet Example

This chapter and the next present a running example of a simple spreadsheet application.

A spreadsheet is a two-dimensional grid of “cells,” and each cell contains a number or string. Professional spreadsheets such as Microsoft Excel provide the ability to perform mathematical operations such as calculating the sum of the values of a set of cells. The spreadsheet example in these chapters does not attempt to challenge Microsoft in the marketplace, but is useful for illustrating the issues of classes and objects.

The spreadsheet application uses two basic classes: Spreadsheet and SpreadsheetCell. Each

Spreadsheet object contains SpreadsheetCell objects. In addition, a SpreadsheetApplication class manages the various Spreadsheets. This chapter focuses on the SpreadsheetCell. Chapter 9 develops the Spreadsheet and SpreadsheetApplication classes.