implement queue using js and some examples

queue.js

function Queue() {
	this.dataSource = [];
	this.enqueue = enqueue;
	this.dequeue = dequeue;
	this.front = front;
	this.back = back;
	this.toString = toString;
	this.empty = empty;


	function enqueue(element) {
		this.dataSource.push(element);
	}

	function dequeue() {
		return this.dataSource.shift();
	}

	function front() {
		return this.dataSource[0];
	}

	function back() {
		return this.dataSource[this.dataSource.length - 1];
	}

	function toString() {
		var resStr = '';
		for (var i = 0; i < this.dataSource.length; ++i) 
			resStr += this.dataSource[i] + "\n";
		return resStr;
	}

	function empty() {
		if (this.dataSource.length == 0)
		   	return true;
		else 
			return false;
	}
}

/*
test queue

var q = new Queue();
q.enqueue('a');
q.enqueue('b');
q.enqueue('c');
console.log(q.toString());
q.dequeue();
console.log(q.toString());
*/

/*
// Assigning Partners at a Square Dance 
function Dancer(name, sex) {
	this.name = name;
	this.sex = sex;
}

function getDancers(males, females) {
	var names = read('dancers.txt').split("\n")	;
	for (var i = 0; i < names.length; ++i)
		names[i] = names[i].trim();
	for(var i = 0; i < names.length; ++i) {
		var dancer = names[i].split(' ');
		var sex = dancer[0];
		var name = dancer[1];
		if (sex == F)
			females.enqueue(new Dancer(name, sex));
		else
			males.enqueue(new Dancer(name, sex));
	} //for
} //getDancers

function dance(males, females) {
	console.log("The dancer parters are\n");
	while(!males.empty() && !females.empty()) {
		person = females.dequeue();
		putstr("Female dancer is: " + person.name);
		person = males.dequeue();
		putstr("and the male dancer is: " + person.name);
	} //while
	console.log('');
}

// test dancer programe
var maleDancers = new Queue();
var femaleDancers = new Queue();
getDancers(maleDancers, femaleDancers);
dance(maleDancers, femaleDancers);
if(!femaleDancers.empty())
	console.log(femaleDancers.front().name + " is waitting to dance");
else
	console.log(maleDancers.front().name + " is waitting to dance");
*/

// radix sort
function distribute(nums, queues, n, digit) {
	for (var i = 0; i < n; ++i) {
		if (digit == 1) 
			queues[nums[i] % 10].enqueue(nums[i]);
		else 
			queues[Math.floor(nums[i] / 10)].enqueue(nums[i]);
	}
}

function collect(queues, nums) {
	var i = 0;
	for(var digit = 0; digit < 10; ++digit) {
		while(!queues[digit].empty()) 
			nums[i++] = queues[digit].dequeue();
	} //for
}

function displayArray(arr) {
	for(var i = 0; i < arr.length; ++i)
		process.stdout.write(arr[i] + " ");
}

// main radix sort
var queues = []
for(i = 0; i < 10; ++i)
	queues[i] = new Queue();

var nums = [];
for(var i = 0; i < 10; ++i) {
	nums[i] = Math.floor(Math.floor(Math.random() * 101));
}
console.log("Before radix sort");
displayArray(nums);
distribute(nums, queues, 10, 1);
collect(queues, nums);
distribute(nums, queues, 10, 10);
collect(queues, nums);
console.log("\nAfter radix sort:")
displayArray(nums);