Queue with pop/push pointer and - Node.js Data Structure

Node.js examples for Data Structure:Queue

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Description

Queue with pop/push pointer and

Demo Code


function Queue() {
  this.length = 5;//from   www. java  2s  .co m
  // this.data = [];
  this.data = new Array(5);
  this.pointerPop = 0;
  this.pointerPush = 0;
}


Queue.prototype.push = function(number) {
  var array = this.data;
  var length = this.length;

  // if the array is full, double the size to allow for more space to push
  if (typeof array[this.pointerPush] === "number") {
    this.pointerPush = length;
    array = array.concat(new Array(length));
    length*= 2;
    array[this.pointerPush] = number;
    this.pointerPush++;
  } else {
    array[this.pointerPush] = number;
    this.pointerPush++;
  }
  if (this.pointerPush >= length) {
    this.pointerPush = 0;
  }
}

Queue.prototype.pop = function() {
  var array = this.data;
  var popped = array[this.pointerPop];
  // handle underflow
  if (array[this.pointerPop] === null) {
    this.pointerPush = 0;
    this.pointerPop = 0;
    throw new Error("pop called on an empty Queue")
  } else {
    array[this.pointerPop] = null;
    this.pointerPop++;
  }
  if (this.pointerPop >= this.length) {
    this.pointerPop = 0;
  }
  return popped;
}





var babyQueue = new Queue();
babyQueue.push(1);
babyQueue.push(2);
babyQueue.push(3);
babyQueue.push(4);
// console.log(babyQueue.pop())
babyQueue.push(5);
babyQueue.push(6);
console.log(babyQueue.pop())
console.log(babyQueue.pop())
console.log(babyQueue.pop())
console.log(babyQueue.pop())
console.log(babyQueue.pop())

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