Cont'd Day1, completed level1 and level2 of Function exercises, still need to finish level3 before merging to master branch

solutions/day-01/functions/level1.js

@@ -0,0 +1,75 @@
+// Declare a function fullName and it takes firstName, lastName as a parameter and it returns your full - name.
+function fullName(firstName,lastName){
+    return `${firstName} ${lastName}`;
+}
+console.log(fullName('Seto', 'Kaiba'));
+
+// Declare a function addNumbers and it takes two parameters and it returns sum.
+function addNumbers(num1,num2){
+    return num1 + num2;
+}
+console.log(addNumbers(4,8));
+
+// Area of a circle is calculated as follows: area = π x r x r. Write a function which calculates _areaOfCircle
+let _areaOfCircle = (radius)=>{
+    let pi = Math.PI;
+    let area = pi * radius * radius;
+    return area;
+}
+console.log(_areaOfCircle(5));
+
+// Temperature in oC can be converted to oF using this formula: oF = (oC x 9/5) + 32. 
+// Write a function which convert oC to oF convertCelciusToFahrenheit.
+let convertCelciusToFahrenheit = (oC) => {
+    let oF = (oC * (9/5)) + 32;
+    return oF;
+}
+console.log(convertCelciusToFahrenheit(20) + `\u00B0F`)
+
+
+/*Body mass index(BMI) is calculated as follows: bmi = weight in Kg / (height x height) in m2. 
+Write a function which calculates bmi. BMI is used to broadly define different weight groups in 
+adults 20 years old or older.Check if a person is underweight, normal, overweight or obese based the information given below.
+
+The same groups apply to both men and women.
+Underweight: BMI is less than 18.5
+Normal weight: BMI is 18.5 to 24.9
+Overweight: BMI is 25 to 29.9
+Obese: BMI is 30 or more */
+let BMI = (weight, height)=>{
+    let bmi = (weight / (height * height)).toFixed(2);
+    let answer = '';
+    switch (true) {
+        case bmi >= 30: answer = `BMI is ${bmi}: You are Obese!`;
+            break;
+        case bmi >=25 && bmi < 30: answer = `BMI is ${bmi}: You are Overweight!`;
+            break;
+        case bmi >= 18.5 && bmi < 25: answer = `BMI is ${bmi}: You are Normal weight!`;
+            break;
+        case bmi < 18.5: answer = `BMI is ${bmi}: You are Underweight!`;
+            break;
+        default:
+            break;
+    }
+    return answer;
+}
+console.log(BMI(73, 1.77));
+
+// Write a function called checkSeason, it takes a month parameter and returns the season:Autumn, Winter, Spring or Summer.
+let checkSeason = (month) => {
+    let season = '';
+    switch(true){
+        case month == 'September' || month == 'October' || month == 'November': season = `The season is Autumn in the month of ${month}`;
+            break;
+        case month == 'December' || month == 'January' || month == 'February': season = `The season is Winter in the month of ${month}`;
+            break;
+        case month == 'March' || month == 'April' || month == 'May': season = `The season is Spring in the month of ${month}`;
+            break;
+        case month == 'June' || month == 'July' || month == 'August': season = `The season is Summer in the month of ${month}`;
+            break;
+        default:
+            break;
+    }
+    return season;
+}
+console.log(checkSeason('May'));

solutions/day-01/functions/level2.js

@@ -0,0 +1,155 @@
+// Quadratic equation is calculated as follows: ax2 + bx + c = 0. 
+// Write a function which calculates value or values of a quadratic equation, solveQuadEquation.
+let solveQuadratic = (...args) =>{
+    if(args.length === 0){
+        return `{0}`;
+    }
+    let a = args[0], b = args[1], c = args[2];
+    let discriminant = b * b - 4 * a * c;
+    let answer = '', real = '', imaginary = '';
+    switch (true) {
+        case discriminant > 0:
+            root1 = (-b + Math.sqrt(discriminant)) / (2 * a);
+            root2 = (-b - Math.sqrt(discriminant)) / (2 * a);
+            answer = `{${root1}, ${root2}}`
+            break;
+        case discriminant == 0:
+            root1 = root2 = -b / (2 * a);
+            answer = `{${root1}}`
+            break;
+        case discriminant < 0:
+            real = (-b / (2 * a)).toFixed(2);
+            imaginary = (Math.sqrt(-discriminant) / (2 * a)).toFixed(2);
+            answer = `{${real} + ${imaginary}i, ${real} - ${imaginary}i}`
+        default:
+            break;
+    }
+    return answer;
+}
+
+console.log(solveQuadratic()) // {0}
+console.log(solveQuadratic(1, 4, 4)) // {-2}
+console.log(solveQuadratic(1, -1, -2)) // {2, -1}
+console.log(solveQuadratic(1, 7, 12)) // {-3, -4}
+console.log(solveQuadratic(1, 0, -4)) //{2, -2}
+console.log(solveQuadratic(1, -1, 0)) //{1, 0}
+
+
+// Declare a function name printArray. It takes array as a parameter and it prints out each value of the array.
+let items = ['Shoe', 'Shirt', 'Pants'];
+let printArray = (array) => {
+    for (const element of array) {
+        console.log(element);
+    }
+}
+printArray(items);
+
+
+// Write a function name showDateTime which shows time in this format: 08/01/2020 04:08 using the Date object.
+let showDateTime = () => {
+    let dateTime = new Date();
+    let month = dateTime.getMonth();
+    let day = dateTime.getDate();
+    let year = dateTime.getFullYear()
+    let time = dateTime.getHours();
+    let minutes = dateTime.getMinutes()
+    if(month < 10 || day < 10){
+        month = `0${month+1}`;
+        day = `0${day}`;
+    }
+    if(time == 0){
+        time = 12;
+    }
+    if(minutes < 10){
+        minutes = `0${minutes}`;
+    }
+
+    console.log(`${month}/${day}/${year} ${time}:${minutes}`);
+    
+}
+showDateTime() // 08/01/2020 04:08
+
+
+// Declare a function name swapValues. This function swaps value of x to y.
+let swapValues = (x,y) => {
+    let temp1 = x;
+    let temp2 = y;
+    x = temp2;
+    y = temp1;
+    console.log(`x => ${x}, y => ${y}`);
+}
+swapValues(3, 4) // x => 4, y=>3
+swapValues(4, 5) // x = 5, y = 4
+
+
+// Declare a function name reverseArray. It takes array as a parameter and it returns the reverse of the array (don't use method).
+let reverseArray = (array) => {
+    return array.reverse();
+}
+console.log(reverseArray([1, 2, 3, 4, 5])) //[5, 4, 3, 2, 1]
+console.log(reverseArray(['A', 'B', 'C'])) //['C', 'B', 'A']
+
+
+// Declare a function name capitalizeArray. It takes array as a parameter and it returns the - capitalizedarray.
+let names = ['john', 'claire', 'billy'];
+let capitalizeArray = (array) => {
+    array.forEach((element,index,arr) => {
+        let capitalized = element.charAt(0).toUpperCase() + element.slice(1).toLowerCase();
+        arr.splice(index,1,capitalized);
+    });
+    return array;
+}
+console.log(capitalizeArray(names));
+
+
+// Declare a function name addItem. It takes an item parameter and it returns an array after adding the item
+let itemArray = ['Milk'];
+let addItem = (item) =>{
+    itemArray.push(item);
+    return itemArray;
+}
+console.log(addItem('Pizza'));
+
+
+// Declare a function name removeItem. It takes an index parameter and it returns an array after removing an ite
+let itemRemove = ['Candy', 'Snacks', 'Vegetables']; 
+let removeItem = (item) =>{
+    itemRemove.splice(itemRemove.indexOf(item),1);
+    return itemRemove;
+}
+console.log(removeItem('Snacks'))
+
+
+// Declare a function name evensAndOdds . It takes a positive integer as parameter and it counts number of evens and odds in the number.
+let evensAndOdds = (positive) => {
+    let evenCount = 0;
+    let oddCount = 0;
+    for(let i = 0; i <= positive; i++){
+        (i % 2 == 0) ? evenCount++ : oddCount++;
+    }
+    console.log(`The number of odds are ${oddCount}\nThe number of evens are ${evenCount}`);
+}
+evensAndOdds(100);
+// The number of odds are 50.
+// The number of evens are 51.
+
+
+// Write a function which takes any number of arguments and return the sum of the arguments
+let sum = (...args) =>{
+    let value = args.reduce((a,b)=>{
+        return a + b;
+    }, 0);
+    console.log(value);
+}
+sum(1, 2, 3); // -> 6
+sum(1, 2, 3, 4) // -> 10
+
+
+// Declare a function name userIdGenerator. When this function is called it generates seven character id. The function return the id, ex: 41XTDbE
+let userIdGenerator = ()=>{
+    // toString(36) is base 36, mixture of binary to ASCII characters. 
+    // substring(2,9) specifies to move 2 right of starting char, and then grab the rest to the right 7 more for total of 9
+    let randomId = ((Math.random() + 1).toString(36).substring(2,9))
+    return randomId;
+}
+console.log(userIdGenerator()); 

solutions/day-01/functions/level3.js

@@ -0,0 +1,18 @@
+//Skipped exercise 1 and 2
+
+
+
+// Call your function shuffleArray, it takes an array as a parameter and it returns a shuffled array
+
+
+
+// Call your function factorial, it takes a whole number as a parameter and it return a factorial of the number
+
+
+
+// Call your function isEmpty, it takes a parameter and it checks if it is empty or not
+
+
+
+// Write a function called average, it takes an array parameter and returns the average of the items. 
+// Check if all the array items are number types. If not give return reasonable feedback.

solutions/day-01/functions/script.js

@@ -0,0 +1,55 @@
+// Function with unlimited number of parameters
+/* - A function declaration provides a function scoped arguments array like object. 
+    Any thing we passed as argument in the function can be accessed from arguments 
+    object inside the functions. Let us see an example*/
+
+// function declaration
+function sumAllNums() {
+    let sum = 0;
+    for (let i = 0; i < arguments.length; i++) {
+        sum += arguments[i];
+    }
+    return sum;
+}
+console.info(sumAllNums(10, 20, 13, 40, 10));  // 93
+
+
+// Unlimited number of parameters in arrow function
+
+/* - Arrow function does not have the function scoped arguments object. 
+To implement a function which takes unlimited number of arguments in 
+an arrow function we use spread operator followed by any parameter name. 
+Any thing we passed as argument in the function can be accessed as array in 
+the arrow function. Let us see an example*/
+
+// Let us access the arguments object
+const addAllNums = (...args) => {
+// console.log(arguments), arguments object not found in arrow function
+// instead we use an a parameter followed by spread operator
+    console.log(args);
+}
+addAllNums(1, 2, 3, 4); // [1, 2, 3, 4]
+
+
+// Self Invoking Functions
+// - Self invoking functions are anonymous functions which do not need to be called to return a value.
+(function (n) {
+  console.log(n * n);
+})(2) // 4, but instead of just printing if we want to return and store the data, we do as shown below
+
+let squaredNum = (function (n) {
+  return n * n;
+})(10)
+console.log(squaredNum);
+
+
+// Function with default parameters
+// - Sometimes we pass default values to parameters, when we invoke the function if we do not pass an argument 
+// the default value will be used. Both function declaration and arrow function can have a default value or values.
+function greetings(name = 'Peter') {
+    let message = `${name}, welcome to 30 Days Of JavaScript!`
+    return message
+}
+console.log(greetings());
+console.log(greetings('Asabeneh'));
+