The Standard Template Library: Hangman

The Standard Template Library: Hangman ‌

So far you’ve seen how to work with sequences of values using arrays. But there are more sophisticated ways to work with collections of values. In fact, working with collections is so common that part of standard C++ is dedicated to doing just that. In this chapter, you’ll get an introduction to this important library. Specifically, you’ll learn to:

n Use vector objects to work with sequences of values

n Use vector member functions to manipulate sequence elements

n Use iterators to move through sequences

n Use library algorithms to work with groups of elements

n Plan your programs with pseudocode

Introducing the Standard Template Library Good game programmers are lazy. It’s not that they don’t want to work; it’s just that they don’t want to redo work that’s already been done—especially if it has

been done well. The STL (Standard Template Library) represents a powerful

collection of programming work that’s been done well. It provides a group of containers, algorithms, and iterators, among other things.

So what’s a container and how can it help you write games? Well, containers let you store and access collections of values of the same type. Yes, arrays let you do

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the same thing, but the STL containers offer more flexibility and power than a simple but trusty array. The STL defines a variety of container types; each works in a different way to meet different needs.

The algorithms defined in the STL work with its containers. The algorithms are common functions that game programmers find themselves repeatedly applying to groups of values. They include algorithms for sorting, searching, copying, merging, inserting, and removing container elements. The cool thing is that the same algorithm can work its magic on many different container types.

Iterators are objects that identify elements in containers and can be manipulated to move among elements. They’re great for, well, iterating through containers. In addition, iterators are required by the STL algorithms.

All of this makes a lot more sense when you see an actual implementation of one of the container types, so that’s up next.

Using Vectors Introducing the Hero’s Inventory 2.0 Program Preparing to Use Vectors Declaring a Vector Using the push_back() Member Function Using the size() Member Function Indexing Vectors Calling Member Functions of an Element Using the pop_back() Member Function Using the clear() Member Function Using the empty() Member Function Using Iterators Introducing the Hero’s Inventory 3.0 Program Declaring Iterators Looping through a Vector Changing the Value of a Vector Element Accessing Member Functions of a Vector Element Using the insert() Vector Member Function Using the erase() Vector Member Function Using Algorithms Introducing the High Scores Program Preparing to Use Algorithms Using the find() Algorithm Using the random_shuffle() Algorithm Using the sort() Algorithm Understanding Vector Performance Examining Vector Growth Examining Element Insertion and Deletion Examining Other STL Containers Planning Your Programs Using Pseudocode Using Stepwise Refinement Introducing Hangman Planning the Game Setting Up the Program Initializing Variables and Constants Entering the Main Loop Getting the Player’s Guess Ending the Game Summary Questions and Answers Discussion Questions Exercises

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