Data Structures and Algorithms with JavaScript

Chapter 12. Sorting Algorithms

Two of the most common operations performed on data stored in a computer are sorting and searching. This has been true since the beginning of the computer industry, so this means that sorting and searching are two of the most studied operations in computer science. Many of the data structures discussed in this book are designed primarily to make sorting and/or searching the data stored in the data structure easier and more efficient.

This chapter will introduce you to some of the basic and advanced algorithms for sorting data. These algorithms depend only on the array as the means of storing data. In this chapter we’ll also look at ways of timing our programs to determine which algorithm is most efficient.

An Array Test Bed

We start this chapter by developing an array test bed to use in support of our study of basic sorting algorithms. We’ll build a class for array data and functions that encapsulates some of the normal array operations: inserting new data, displaying array data, and calling the different sorting algorithms. Included in the class is a swap() function we will use to exchange elements in the array.

Example 12-1 shows the code for this class.

Example 12-1. Array test bed class

function CArray(numElements) {
   this.dataStore = [];
   this.pos = 0;
   this.numElements = numElements;
   this.insert = insert;
   this.toString = toString;
   this.clear = clear;
   this.setData = setData;
   this.swap = swap;

   for (var i = 0; i < numElements; ++i) {
      this ...