Fix quadractic probing overflowing the array (#21)

function HashTable(size) {
    this.size = size;
    this.keys = this.initArray(size);
    this.values = this.initArray(size);
    this.limit = 0;
}

HashTable.prototype.get = function(key) {
    var hashedIndex = this.hash(key);

    while (this.keys[hashedIndex] != key) {
        hashedIndex++;

        hashedIndex = hashedIndex % this.size;

    }
    return this.values[hashedIndex];
}

HashTable.prototype.hash = function(key) {
    // Check if int
    if (!Number.isInteger(key)) throw 'must be int';
    return key % this.size;
}

HashTable.prototype.initArray = function(size) {
    var array = [];
    for (var i = 0; i < size; i++) {
        array.push(null);
    }
    return array;
}

HashTable.prototype.put = function(key, value) {
    if (this.limit >= this.size) throw 'hash table is full'

    var hashedIndex = this.hash(key),
        squareIndex = 1;

    // quadratic probing
    while (this.keys[hashedIndex % this.size] != null) {
        hashedIndex += Math.pow(squareIndex, 2);
        squareIndex++;
    }

    this.keys[hashedIndex % this.size] = key;
    this.values[hashedIndex % this.size] = value;
    this.limit++;
}

HashTable.prototype.get = function(key) {

    var hashedIndex = this.hash(key),
        squareIndex = 1;

    while (this.keys[hashedIndex % this.size] != key) {
        hashedIndex += Math.pow(squareIndex, 2);
        hashedIndex = hashedIndex % this.size;
        squareIndex++;
    }
    return this.values[hashedIndex % this.size];
}

var exampletable = new HashTable(13);
exampletable.put(7, "hi");
exampletable.put(20, "hello");
exampletable.put(33, "sunny");
exampletable.put(46, "weather");
exampletable.put(59, "wow");
exampletable.put(72, "fourty");
exampletable.put(85, "happy");
exampletable.put(98, "sad");

Chapter11(HashTables).js

@@ -68,39 +68,34 @@ exampletable.put(85, "happy");
 exampletable.put(98, "sad");
 
 
-
-
 HashTable.prototype.put = function(key, value) {
     if (this.limit >= this.size) throw 'hash table is full'
 
     var hashedIndex = this.hash(key),
         squareIndex = 1;
 
     // quadratic probing
-    while (this.keys[hashedIndex] != null) {
+    while (this.keys[hashedIndex % this.size] != null) {
         hashedIndex += Math.pow(squareIndex, 2);
-
-        hashedIndex
         squareIndex++;
     }
 
-    this.keys[hashedIndex] = key;
-    this.values[hashedIndex] = value;
+    this.keys[hashedIndex % this.size] = key;
+    this.values[hashedIndex % this.size] = value;
     this.limit++;
 }
 
 HashTable.prototype.get = function(key) {
+
     var hashedIndex = this.hash(key),
         squareIndex = 1;
 
-    while (this.keys[hashedIndex] != key) {
+    while (this.keys[hashedIndex % this.size] != key) {
         hashedIndex += Math.pow(squareIndex, 2);
-
         hashedIndex = hashedIndex % this.size;
         squareIndex++;
     }
-
-    return this.values[hashedIndex];
+    return this.values[hashedIndex % this.size];
 }
 
 

errata.md

@@ -134,6 +134,79 @@ function bubbleSort(array) {
 }
 ```
 
+### Page 158
+
+On **page 158**: Using Quadratic Probing [Summary of error]:
+
+
+**Before**:
+```javascript
+HashTable.prototype.get = function(key) {
+    var hashedIndex = this.hash(key),
+        squareIndex = 1;
+
+    while (this.keys[hashedIndex] != key) {
+        hashedIndex += Math.pow(squareIndex, 2);
+
+        hashedIndex = hashedIndex % this.size;
+        squareIndex++;
+    }
+
+    return this.values[hashedIndex];
+}
+
+
+HashTable.prototype.put = function(key, value) {
+    if (this.limit >= this.size) throw 'hash table is full'
+
+    var hashedIndex = this.hash(key);
+
+    while (this.keys[hashedIndex] != null) {
+        hashedIndex++;
+
+        hashedIndex = hashedIndex % this.size;
+
+    }
+    this.keys[hashedIndex] = key;
+    this.values[hashedIndex] = value;
+    this.limit++;
+}
+```
+
+**After**:
+```javascript
+HashTable.prototype.put = function(key, value) {
+    if (this.limit >= this.size) throw 'hash table is full'
+
+    var hashedIndex = this.hash(key),
+        squareIndex = 1;
+
+    // quadratic probing
+    while (this.keys[hashedIndex % this.size] != null) {
+        hashedIndex += Math.pow(squareIndex, 2);
+        squareIndex++;
+    }
+
+    this.keys[hashedIndex % this.size] = key;
+    this.values[hashedIndex % this.size] = value;
+    this.limit++;
+}
+
+HashTable.prototype.get = function(key) {
+
+    var hashedIndex = this.hash(key),
+        squareIndex = 1;
+
+    while (this.keys[hashedIndex % this.size] != key) {
+        hashedIndex += Math.pow(squareIndex, 2);
+        hashedIndex = hashedIndex % this.size;
+        squareIndex++;
+    }
+    return this.values[hashedIndex % this.size];
+}
+```
+
+
 ***
 
 ### page 183