Since the introduction of the STL (Standard Template Library) the use of functors has been a prevalent part of writing C++. Most of the STL algorithms require the use of a functor. For example, the std::transform requires a function object that, given an input of the current value of the current position, it will return […]
In the earlier article, Lowest Common Ancestor (BST), I discussed how you can use the special ordering of a Binary Search Tree to quickly and easily identify the Lowest Common Ancestor of two nodes. Of course, not all trees are BSTs and so in this article we’ll look at a way of finding the LCA in […]
On all future code related posts, for all full working code examples, I’ll be provided a link to the Ideone online code editor. It’s a little like pastebin but with the bonus of allowing you to both fork and compile the code online.
The Binary Search Tree (BST) is a tree like data structure that allows for the quick lookup of data. They work by storing inserted data in a tree like structure that uses the “divide and conquer” approach to locate data. Each node in the tree has, at most, two children. The left hand side (lhs) node […]
You work in a bar, pouring pints for the locals. One of your regulars comes in; he's looking pretty grumpy today. "Whiskey" he snaps. You put down a glass and pour. You finish pouring and he necks back the drink. "Again", he snaps. Again, you pour and as soon as you finish he necks it. […]
The C++11 standard introduced so called Variadic Templates. These have many uses, one of which is the ability to write functions that take any number of arguments without having to mess around with C-style non-type safe "var-args" and printf like format specifiers.
In my previous article I discussed the difference between up-cast and down-cast and explained why down-casting is rarely a good idea (or even necessary). That said, there are a few times when down-casting is valid and so this article shows how to do so, safely, in C++.
When working with objects that have an inheritance model you basically have an inverted tree that represents your object hierarchy. Contrary to a normal everyday trees, an inheritance tree has its root at the top. In other words, the root of the tree represents the base class and anything below it represents a more derived […]
One of the problems any developer will eventually have to resolve is one of latency; specifically, being able to retrieve and process data in a timely fashion. This issue can come in many guises but they generally manifest as needing to read data from a backing store that cannot deliver the high performance needed by […]
The C and C++ standards documents can be a bit of a beast to trawl through and quite often you’ll find yourself reading the same sentence a number of times trying to fathom out what it is actually saying. It’s just like when you read the EULA for a software product; lots of big words […]
The C++03 standard treats temporary types as r-values (types only meant to go on the right hand side of an assignment expression). As such, it is only possible to bind a temporary to a const reference type. This is a somewhat arbitrary and, often, frustrating rule. The original idea was that there would be no […]
During my numerous years as a software engineer I have spent many an occasion developing solutions to combat Spam. This article introduces the origins of spam and then looks at a number of ways it can be detected.
In case you’ve never heard of it before, Boost is a set of peer reviewed libraries for C++. They provide a lot of features that are sorely missing from the standard C++ libraries and are probably the closest C++ developers have to a standard development toolkit. In fact, Boost is so useful that a number […]
A good friend of my asked me how to get started in meta-template programming. Of course, the first thing is to know C++ and know it well. Other than that, I think my best advise is to ensure you completely understand how the C++ template generation process works. For example, if you don’t know what […]
Today I had the privilege of a job interview with one of the leading companies in the online streaming music space. I’d like to think the interview went well, although I was incredibly nervous and my brain decided it was going to operate in a way that suggested it was wading through treacle; but I […]
This article is going to cover a typical interview test question, which asks you to find the missing number in an array. The array is N elements in size and contains all the numbers 1 to N. The numbers can be in any order but will never repeat. One of the numbers is missing and […]
Virtual functions and default parameter arguments are a staple of all C++ programmers, but you might get more than you bargained for if you decide to mix and match them. Try this little quiz and see if your coders intuition is correct.
Templates are a hugely powerful feature of C++. They allow you to do so many different and cool things. Unfortunately, templates do have a bit of a reputation for having rather nasty syntax and for the most part this reputation is quite well deserved. This little quiz shows an example of some template syntax that […]
Linked lists are an interviewers favourite subject matter. Whilst they are pretty easy to understand, at least in principle, they do require a little bit of brain warping to get your head around what’s going on under the hood. Of the common questions about linked lists I’ve come across, this quiz tackles the most common: […]
Included as part of the C++ Standard Template Library (STL) is a collection of generic containers. Each of these containers serves a different purpose and has different pros and cons. It is often difficult to decide which container to use and when to use it.
This article is a discussion on smart pointers, what they are and why they are important to C++ programmers. Following the primary discussion I present a simple implementation of a reference counted smart pointer and show a simple example of using it. Although this article does not go into detail about how to develop a […]
Sometimes, just because you can do something doesn’t mean you should. Unfortunately, the C++ Standards Council missed that memo when they ratified the exception specifiers. To find out why, try this little quiz.
Need to store objects in an STL container? Need polymorphic behaviour meaning you’ll need to store pointers to a base class? Want to use a smart pointer to avoid memory leaks? Planning on using auto_ptr because it’s available as part of C++? Before you go any further, try this little quiz.
Ubiquitous use of smart pointers can prevent memory leaks and make for much easier to read and understand code. Unfortunately, as with most things C++, there are some caveats you need to be aware of otherwise your attempts to write robust code could very well come back to bite you. This little quiz shows how […]
When working with STL containers we generally use iterators to access, manipulate and enumerate the contents. This almost becomes second nature and it’s very easy to go on auto-pilot and end up coding an innocuous looking bit of code that can contain a rather nasty surprise. This little quiz shows just one example of how […]