Javascript Data Structure Tutorial - Javascript Selection Sort
The sorting algorithm works by starting at the beginning of the array and comparing the first element with the remaining elements.
After examining all the elements, the smallest element is placed in the first position, and the algorithm moves to the second position.
This process continues until the algorithm arrives at the next to last position in the array.
Nested loops are used in the selection sort algorithm.
The outer loop moves from the first element in the array to the next to last element; the inner loop moves from the second array element to the last element.
Example
function MyArray(numElements) { //w w w .j a va2 s . c o m
this.dataStore = [];
this.pos = 0;
this.numElements = numElements;
this.insert = insert;
this.toString = toString;
this.clear = clear;
this.setData = setData;
this.swap = swap;
this.selectionSort = selectionSort;
for (var i = 0; i < numElements; ++i) {
this.dataStore[i] = i;
}
}
function setData() {
for (var i = 0; i < this.numElements; ++i) {
this.dataStore[i] = Math.floor(Math.random() * (this.numElements+1));
}
}
function clear() {
for (var i = 0; i < this.dataStore.length; ++i) {
this.dataStore[i] = 0;
}
}
function insert(element) {
this.dataStore[this.pos++] = element;
}
function toString() {
var retstr = "";
for (var i = 0; i < this.dataStore.length; ++i) {
retstr += this.dataStore[i] + " ";
if (i > 0 && i % 10 == 0) {
retstr += "\n";
}
}
return retstr;
}
function swap(arr, index1, index2) {
var temp = arr[index1];
arr[index1] = arr[index2];
arr[index2] = temp;
}
function selectionSort() {
var min, temp;
for (var outer = 0; outer <= this.dataStore.length-2; ++outer) {
min = outer;
for (var inner = outer + 1; inner <= this.dataStore.length-1; ++inner) {
if (this.dataStore[inner] < this.dataStore[min]) {
min = inner;
}
}
swap(this.dataStore, outer, min);
}
}
var numElements = 10;
var mynums = new MyArray(numElements);
mynums.setData();
console.log(mynums.toString());
mynums.selectionSort();
console.log();
console.log(mynums.toString());
The code above generates the following result.
