Merge pull request uagc-it-readiness#5 from robinsonaaron/master

robinsonaaron · web-flow · commit 7e9352bee660 · 2016-12-08T20:26:34.000-06:00
Added JavaScript assignment 3
diff --git a/02-javascript/assignment-3/README.md b/02-javascript/assignment-3/README.md
@@ -0,0 +1,21 @@
+The sum of a range
+
+The introduction of this book alluded to the following as a nice way to compute the sum of a range of numbers:
+
+console.log(sum(range(1, 10)));
+Write a range function that takes two arguments, start and end, and returns an array containing all the numbers from start up to (and including) end.
+
+Next, write a sum function that takes an array of numbers and returns the sum of these numbers. Run the previous program and see whether it does indeed return 55.
+
+As a bonus assignment, modify your range function to take an optional third argument that indicates the “step” value used to build up the array. If no step is given, the array elements go up by increments of one, corresponding to the old behavior. The function call range(1, 10, 2) should return [1, 3, 5, 7, 9]. Make sure it also works with negative step values so that range(5, 2, -1) produces [5, 4, 3, 2].
+
+```
+console.log(range(1, 10));
+// → [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+console.log(range(5, 2, -1));
+// → [5, 4, 3, 2]
+console.log(sum(range(1, 10)));
+// → 55
+```
+
+source: [Eloquent JavaScript](http://eloquentjavascript.net/04_data.html)
diff --git a/02-javascript/assignment-3/index.html b/02-javascript/assignment-3/index.html
@@ -0,0 +1,9 @@
+<html>
+<head>
+  <script type="text/javascript" src="main.js" ></script>
+</head>
+<body>
+  <input type="button" onclick="testRangeFunction()" value="Test range function" />
+  <input type="button" onclick="testSumFunction()" value="Test sum array function" />
+</body>
+</html>
diff --git a/02-javascript/assignment-3/main.js b/02-javascript/assignment-3/main.js
@@ -0,0 +1,66 @@
+function range(start, end) {
+    // your code here
+}
+
+function sum(array) {
+    // your sum function here
+}
+
+
+// do not edit below this line
+
+// test the range function
+function testRangeFunction() {
+    var resultString = "testRangeFunction:";
+
+    if ([1,2,3,4,5,6,7,8,9,10].equals(range(1, 10)) 
+        && [0,1,2,3,4,5].equals(range(0, 5)))
+        resultString += "pass";
+    else
+        resultString += "fail";
+
+    console.log(resultString);
+}
+
+// test the range function
+function testSumFunction() {
+    var resultString = "testSumFunction:";
+
+    if (sum(range(1,10) === 55))
+        resultString += "pass";
+    else
+        resultString += "fail";
+
+    console.log(resultString);
+}
+
+
+// Warn if overriding existing method
+if(Array.prototype.equals)
+    console.warn("Overriding existing Array.prototype.equals. Possible causes: New API defines the method, there's a framework conflict or you've got double inclusions in your code.");
+// attach the .equals method to Array's prototype to call it on any array
+Array.prototype.equals = function (array) {
+    // if the other array is a falsy value, return
+    if (!array)
+        return false;
+
+    // compare lengths - can save a lot of time 
+    if (this.length != array.length)
+        return false;
+
+    for (var i = 0, l=this.length; i < l; i++) {
+        // Check if we have nested arrays
+        if (this[i] instanceof Array && array[i] instanceof Array) {
+            // recurse into the nested arrays
+            if (!this[i].equals(array[i]))
+                return false;       
+        }           
+        else if (this[i] != array[i]) { 
+            // Warning - two different object instances will never be equal: {x:20} != {x:20}
+            return false;   
+        }           
+    }       
+    return true;
+}
+// Hide method from for-in loops
+Object.defineProperty(Array.prototype, "equals", {enumerable: false});
