update

exercises/part1-fizzbuzz/index.js

@@ -18,12 +18,40 @@ Hint 2. Consider how modulo (calculating the remainder of a division problem) mi
 Believe it or not, this is a common programming challenge in job interviews!
 
 ===================== */
-
-/* =====================
-
-Start code
-
-===================== */
+function IfThree(n){
+    if (n % 3 ==0){
+        return "Fizz"
+    } else {
+        return n
+    }
+}
+
+function IfFive(n){
+    if (n % 5 ==0){
+        return "Buzz"
+    } else {
+        return n
+    }
+}
+
+
+let s = '';
+
+for (i = 1; i<101; i++) {
+    if (i % 3 == 0) {
+        if (i % 5 == 0){
+            s += "FizzBuzz" +'\n';
+        } else{
+            s += "Fizz" +'\n';
+        }
+
+    }
+    else if(i % 5 ==0 ) {
+        s += "Buzz" +'\n';
+    }
+    else {s += i.toString}
+}
+console.log(s);
 
 
 

exercises/part2-basic-functions/index.js

@@ -13,7 +13,7 @@ in years. (Let's just assume this person was born January 1 at 12:01 AM)
 Example: "age(2000) should return 22"
 ===================== */
 
-let age = (birthYear) => {};
+let age = (birthYear) => { return 2022-birthYear };
 
 console.log('age success:', age(1971) === 51);
 
@@ -22,7 +22,7 @@ Instructions: Write a function that adds one to the number provided
 Example: "plusOne(2) should return 3"
 ===================== */
 
-let plusOne = () => {};
+let plusOne = (i) => { return i+1 };
 
 console.log('plusOne success:', plusOne(99) === 100);
 
@@ -31,7 +31,7 @@ Instructions: Write a function that multiplies the number provided by three
 Example: "timesThree(2) should return 6"
 ===================== */
 
-let timesThree = () => {};
+let timesThree = (i) => { return i*3 };
 
 console.log('timesThree success:', timesThree(33) === 99);
 
@@ -40,7 +40,7 @@ Instructions: Write a function that adds two given numbers
 Example: "add(2, 3) should return 5"
 ===================== */
 
-let add = () => {};
+let add = (x,y) => { return x+y };
 
 console.log('add success:', add(4, 6) === 10);
 
@@ -49,7 +49,7 @@ Instructions: Write a function that multiplies two given numbers
 Example: "multiply(2, 3) should return 6"
 ===================== */
 
-let multiply = () => {};
+let multiply = (x,y) => { return x*y };
 
 console.log('multiply success:', multiply(4, 6) === 24);
 
@@ -58,7 +58,7 @@ Instructions: "Write a function that returns the value of an array at a specifie
 Example: "valueAtIndex(['Mercury', 'Venus', 'Earth', 'Mars'], 2) should return 'Earth'"
 ===================== */
 
-let valueAtIndex = () => {};
+let valueAtIndex = (list, i) => { return list[i] };
 
 console.log('valueAtIndex success:', valueAtIndex([9, 8, 7, 6, 5], 2) === 7);
 
@@ -67,22 +67,39 @@ Instructions: "Write a function that returns the value of an object at a specifi
 Example: "valueAtKey({'name': 'Nathan'}, 'name') should return 'Nathan'"
 ===================== */
 
-let valueAtKey = () => {};
+let valueAtKey = (dic, i) => { 
+   // let arry = Object.entries(list);
+    return dic[i]
+};
 
 console.log('valueAtKey success:', valueAtKey({ 'foo': 'bar' }, 'foo') === 'bar');
 
 /* =====================
 Instructions: Write a function that returns true if a number is even.
 ===================== */
 
-let isEven = () => {};
+let isEven = (i) => {
+    if(i % 2 == 0) {
+        return true
+    }
+    else {
+        return false
+    }
+};
 
 console.log('isEven success:', isEven(2) === true && isEven(3) === false);
 
 /* =====================
 Instructions: Write a function that returns true if a number is odd.
 ===================== */
 
-let isOdd = () => {};
+let isOdd = (i) => {
+    if (i % 2 == 1){
+        return true
+    }
+    else {
+        return false
+    }
+};
 
 console.log('isOdd success:', isOdd(4) === false && isOdd(5) === true);

exercises/part3-iterators/index.js

@@ -16,7 +16,15 @@ Instructions: Write a function which counts the number of times a value occurs i
 Example: countItem(['a', 'b', 'a'], 'a') should return 2
 ===================== */
 
-let countItem = (arr, item) => {};
+let countItem = (arr, item) => {
+  let cnt = 0;
+  for (i of arr) {
+    if (item == i){
+      cnt += 1;
+    }
+  }
+  return cnt;
+};
 
 console.log('countItem success:', countItem([1, 2, 3, 4, 5, 4, 4], 4) === 3);
 
@@ -27,8 +35,22 @@ Instructions: Write a function which takes an array and returns a new array with
   original array.
 ===================== */
 
-let isEven = (n) => {};
-let filterEven = (arr) => {};
+let isEven = (n) => {
+  if ( n % 2 == 0){
+    return true
+  } 
+    return false
+};
+
+let filterEven = (arr) => {
+  let EvenArr = [];
+  for (let i = 0; i < arr.length; i++ ){
+    if(isEven(arr[i])) {
+      EvenArr.push(arr[i]);
+    }
+  }
+  return EvenArr
+};
 
 console.log('filterEven success:', _(filterEven([1, 2, 3, 4, 5, 4, 4])).isEqual([2, 4, 4, 4]));
 
@@ -38,8 +60,21 @@ Instructions: Write a function which takes an array and returns a new array with
   function MUST use the isOdd function and MUST NOT change the original array.
 ===================== */
 
-let isOdd = (n) => {};
-let filterOdd = (arr) => {};
+let isOdd = (n) => {
+  if ( n % 2 != 0){
+    return true
+  } 
+    return false
+};
+let filterOdd = (arr) => {
+  let OddArr = [];
+  for (let i = 0; i < arr.length; i++ ){
+    if(isOdd(arr[i])) {
+      OddArr.push(arr[i]);
+    }
+  }
+  return OddArr
+};
 
 console.log('filterOdd success:', _(filterOdd([1, 2, 3, 4, 5, 4, 4])).isEqual([1, 3, 5]));
 
@@ -50,8 +85,16 @@ Instructions: Write a function which takes an array and returns a new array with
   original array.
 ===================== */
 
-let plusOne = (n) => {};
-let mapIncrement = (arr) => {};
+let plusOne = (n) => {
+  return n+1
+};
+let mapIncrement = (arr) => {
+  let PlusArr = [];
+  for (let i =0; i < arr.length; i++){
+    PlusArr.push(plusOne(arr[i]));
+  }
+  return PlusArr
+};
 
 console.log('mapIncrement success:', _(mapIncrement([1, 2, 3, 4, 5, 4, 4])).isEqual([2, 3, 4, 5, 6, 5, 5]));
 
@@ -62,8 +105,16 @@ Instructions: Write a function which takes an array and returns a new array with
   original array.
 ===================== */
 
-let timesThree = (n) => {};
-let mapTriple = (arr) => {};
+let timesThree = (n) => {
+  return n*3;
+};
+let mapTriple = (arr) => {
+  let TimesArr = [];
+  for (let i =0; i < arr.length; i++){
+    TimesArr.push(timesThree(arr[i]));
+  }
+  return TimesArr
+};
 
 console.log('mapTriple success:', _(mapTriple([1, 2, 3, 4, 5, 4, 4])).isEqual([3, 6, 9, 12, 15, 12, 12]));
 
@@ -74,8 +125,17 @@ Instructions: Write a function which takes an array and returns the sum of all
   array.
 ===================== */
 
-let add = (n1, n2) => {};
-let reduceSum = (arr) => {};
+let add = (n1, n2) => {
+  return n1+n2;
+};
+let reduceSum = (arr) => {
+  let s=0;
+  for (i =0; i< arr.length; i++){
+    s = add(s, arr[i]);
+  }
+  return s;
+
+};
 
 console.log('reduceSum success:', reduceSum([1, 2, 3, 4, 5, 4, 4]) === 23);
 
@@ -86,7 +146,15 @@ Instructions: Write a function which takes an array and returns the product of
   original array.
 ===================== */
 
-let multiply = (n1, n2) => {};
-let reduceProduct = (arr) => {};
+let multiply = (n1, n2) => {
+  return n1*n2;
+};
+let reduceProduct = (arr) => {
+  let s=1;
+  for (i=0; i<arr.length; i++){
+    s = multiply(s,arr[i]);
+  }
+  return s;
+};
 
 console.log('reduceProduct success:', reduceProduct([1, 2, 3, 4, 5, 4, 4]) === 1920);

exercises/part4-functions-as-values/index.js

@@ -17,7 +17,15 @@ Instructions: Write a function which takes an array and returns a new array,
   on whether the item satisfies some condition).
 ===================== */
 
-let filter = (arr, pred) => {};
+let filter = (arr, pred) => {
+  let newarr = [];
+  for (let i = 0; i < arr.length ; i++){
+    if(pred(arr[i])){
+      newarr.push(arr[i]);
+    }
+  }
+  return newarr;
+};
 
 console.log('filter success #1:', _(filter([1, 2, 3, 4, 5, 4, 4], isEven)).isEqual([2, 4, 4, 4]));
 console.log('filter success #2:', _(filter([1, 2, 3, 4, 5, 4, 4], isOdd)).isEqual([1, 3, 5]));
@@ -27,7 +35,13 @@ Instructions: Write a function which takes an array and returns a new array,
   where each item has a function applied to it.
 ===================== */
 
-let map = (arr, func) => {};
+let map = (arr, func) => {
+  let newArr = [];
+  for (let i =0; i < arr.length; i++){
+    newArr.push(func(arr[i]));
+  }
+  return newArr;
+};
 
 console.log('map success #1:', _(map([1, 2, 3, 4, 5, 4, 4], plusOne)).isEqual([2, 3, 4, 5, 6, 5, 5]));
 console.log('map success #2:', _(map([1, 2, 3, 4, 5, 4, 4], timesThree)).isEqual([3, 6, 9, 12, 15, 12, 12]));
@@ -52,7 +66,13 @@ Instructions: Write a function which takes an array and returns the value of
 
 ===================== */
 
-let reduce = (arr, func, initial) => {};
+let reduce = (arr, func, initial) => {
+  let r = initial;
+  for( i = 0 ; i<arr.length ; i++){
+    r = func(r, arr[i]);
+  }
+  return r;
+};
 
 console.log('reduce success #1:', reduce([1, 2, 3, 4, 5, 4, 4], add, 0) === 23);
 console.log('reduce success #2:', reduce([1, 2, 3, 4, 5, 4, 4], multiply, 1) === 1920);
@@ -65,6 +85,12 @@ Bonus: Create a function called sumSquares that takes an array and returns
   `multiply` functions that you developed before).
 ===================== */
 
-let sumSquares = (arr) => {};
+let squared = (i) =>{
+  return i * i;
+}
+
+let sumSquares = (arr) => {
+  return reduce(map(arr, squared), add, 0);
+};
 
 console.log('sumSquares success:', sumSquares([1, 2, 3, 4]) === 30);