Previously we’ve seen how variables are passed by value. While this works well in many cases, it means that the variable has to be duplicated when it is passed to the function. For large, and/or complicated, variables – like when we start using objects, this can take precious time and resources. However, C++ offers us…
Many times, two or more analysis classes are related to one another in some fashion or another. In UML this is called associations. With Object Oriented code, we often ask if two classes are related or associated through a is-a or has-a type relationship. For example: a car (and object) has a(n) engine (an other…
Operations define the behaviors of the object. While there are lots of different behaviors, they can often be broken down into four main categories. Those that manipulate data often have a set in their function name. Such as setPassword(). Those that check the state of an object usually return a boolean value, and use the…
Attributes help describe a class. They are what help us differentiate from one object and another. Attributes should be relevant to the system that you are building. So two similar objects might have very different attributes based upon how it is used. Consider a College Student Athlete. The data needed for your sports team is…
Some things are easy to identify as a class. For example, if you look around the room, you can find lots of physical objects which can be made into classes. However, in a software environment, this may not always be as easy to identify. So look at the following questions to start to identify what…
Variables must be declared before they can be used in C++. This is why a lot of developers follow the best practice of defining the variables at the top of a function. Variable Scope By default variables can be used in the function that they are created. This is their scope, is is often referred…
Calling a function has a performance penalty because you have to create variables, specify scope, pause the current variables and push data onto the call stack, just to name a few reasons. C++ allows you to define an inline function, which should be short, to improve the performance. In doing so, the compiler will actually…
The next thing one should know about when working with the size of an element is margins, padding, and width. Margins Margins are simply the space between two elements. We can specify the margin to be the same all the way around an element, the same on the left and right and a different value…
