EloquentJS HW Submission

chapter04.js

@@ -10,41 +10,89 @@
 // Problem 1: The sum of a range
 function range(start, end, step=1) {
   // Your code here
+  var array = [];
+  for (var i = start; step > 1 || step === undefined ? i <= end : i >= end; step ? i = i + step : i++)
+      array.push(i);
+  return array;
 }
 
 function sum(array) {
   // Your code here
+  var result = 0;
+  for(var i=0; i<array.length; i++){
+    result+=array[i];
+  }
+  return result;
 }
 
+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
+
 // Problem 2: Reversing an Array
 function reverseArray(array) {
   // Your code here
+  var newArray = [];
+  for (var i = array.length - 1; i >= 0; i--)
+      newArray.push(array[i]);
+  return newArray;
 }
 
 function reverseArrayInPlace(array) {
   // Your code here
+  var index = 0;
+  for (var i = 0; i < array.length / 2; i++) {
+      index = array[i];
+      array[i] = array[array.length - i - 1];
+      array[array.length - i - 1] = index;
+  } 
 }
 
+console.log(reverseArray(["A", "B", "C"]));
+// ? ["C", "B", "A"];
+var arrayValue = [1, 2, 3, 4, 5];
+reverseArrayInPlace(arrayValue);
+console.log(arrayValue);
+// ? [5, 4, 3, 2, 1]
+
 // Problem 3: A List
 function arrayToList(array) {
   // Your code here
+  var list = null;
+  for (var i = array.length - 1; i >= 0; i--)
+    list = {value: array[i], rest: list};
+  return list;
 }
 
 function listToArray(list) {
   // Your code here
+  var array = [];
+  for (var node = list; node; node = node.rest)
+    array.push(node.value);
+  return array;
 }
 
 function nth(list, position) {
   // Your code here
+  if (!list)
+    return undefined;
+  else if (position == 0)
+    return list.value;
+  else
+    return nth(list.rest, position - 1);
 }
 
 function prepend(element, list) {
   // Your code here
+  return {value: value, rest: list};
 }
 
 // Problem 4: Deep comparison
 function deepEqual(obj1, obj2) {
-  // Your code here
+  // Your code heres
 }
 
 

chapter05.js

@@ -21,12 +21,19 @@ ancestry.forEach(function(person) {
 // Problem 1: Flattening
 function flatten(arrays) {
   // Your code here
+  console.log(arrays.reduce(function(flat, current) {
+    return flat.concat(current);
 }
 
 // Problem 2: Mother-child age difference
 /* This must return the average age difference instead of printing it */
 function averageMomChildAgeDiff() {
   // Your code here
+  var differences = ancestry.filter(function(person) {
+    return byName[person.mother] != null;
+  }).map(function(person) {
+    return person.born - byName[person.mother].born;
+  });
 }
 
 // Problem 3: Historical life expectancy
@@ -35,6 +42,28 @@ function averageMomChildAgeDiff() {
  */
 function averageAgeByCentury() {
   // Your code here
+  function groupBy(array, groupOf) {
+    var groups = {};
+    array.forEach(function(element) {
+      var groupName = groupOf(element);
+      if (groupName in groups)
+        groups[groupName].push(element);
+      else
+        groups[groupName] = [element];
+    });
+    return groups;
+  }
+
+  var byCentury = groupBy(ancestry, function(person) {
+    return Math.ceil(person.died / 100);
+  });
+
+  for (var century in byCentury) {
+    var ages = byCentury[century].map(function(person) {
+      return person.died - person.born;
+    });
+    console.log(century + ": " + average(ages));
+  }
 }
 
 

chapter13.js

@@ -10,6 +10,28 @@
 // Problem 1: Build table
 function buildTable(data) {
   // Your code here
+  var table = document.createElement("table");
+
+    var fields = Object.keys(data[0]);
+    var headRow = document.createElement("tr");
+    fields.forEach(function(field) {
+      var headCell = document.createElement("th");
+      headCell.textContent = field;
+      headRow.appendChild(headCell);
+    });
+    table.appendChild(headRow);
+    data.forEach(function(object) {
+      var row = document.createElement("tr");
+      fields.forEach(function(field) {
+        var cell = document.createElement("td");
+        cell.textContent = object[field];
+        if (typeof object[field] == "number")
+          cell.style.textAlign = "right";
+        row.appendChild(cell);
+      });
+      table.appendChild(row);
+    });
+    return table;
 }