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javascript-intro-lab/lab.js

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+// Practice 1: Create Variables
+// Create variables
+let name = "Lan Nguyen";
+let age = 33; 
+let favoriteColor = "orange";
+let likesCoding = true;
+
+// Print them
+console.log("Name:", name);
+console.log("Age:", age);
+console.log("Favorite Color:", favoriteColor);
+console.log("Likes Coding:", likesCoding);
+
+//## Check for Understanding
+
+//Answer these questions in comments in your code:
+
+//1. What is a variable? It's a named container that stores information.
+//2. What is the difference between `let` and `const`?
+//`let` is used when a variable value can change
+//`const` is used when a variable value should not change
+//3. What does `console.log()` do? print information to the console for debuging or display purpose
+//------
+//# Part 2: Conditionals
+
+//## What is a Conditional? A conditional allows your program to make decisions.
+
+//## Practice 2: Write Conditionals
+
+//### Task A
+
+//Create a variable called `temperature`.
+//Write a conditional that prints:
+//* `"It is cold."` if the temperature is below 60
+//* `"It is warm."` if the temperature is 60 or higher
+
+let temperature = 55; 
+
+if (temperature < 60) {
+    console.log("It is cold.");
+} else {
+    console.log("It is warm.");
+}
+
+//### Task B
+//Create a variable called `password`.
+//Write a conditional that prints:
+//* `"Access granted"` if the password is `"javascript123"`
+//* `"Access denied"` otherwise
+
+let password = "javascript123";
+if(password === "javascript123"){
+    console.log("Access granted");
+}else{
+    console.log("Access denied");
+}
+
+//### Task C
+
+//Create a variable called `hour`.
+//Write a conditional that prints:
+
+//* `"Good morning"` if the hour is less than 12
+//* `"Good afternoon"` if the hour is between 12 and 17
+//* `"Good evening"` otherwise
+
+let hour=10;
+if(hour <12){
+    console.log("Good morning");
+} else if( hour >= 12 && hour <=17){
+    console.log("Good evening");
+}
+
+//---
+
+//## Check for Understanding
+
+//Answer these questions in comments:
+
+//1. What is the purpose of an `if` statement? check if a condition is true and execute code accordingly.
+//2. When would you use `else if`? when I want to check multiple conditions in a sequence, and execute different code for each condition.
+//3. What does `===` check for? it checks if two values are equal in both value and type.
+
+//--
+
+//## Practice 3: Build Functions
+//### Task A
+//Create a function called `sayHello` that prints a greeting.
+//### Task B
+
+//Create a function called `favoriteFood` that accepts one parameter and prints:
+
+//'''javascript
+//"My favorite food is ____."
+
+function sayHello(name) {
+  console.log("Hello, " + name);
+
+}sayHello("Joseph");
+function favoriteFood(food){
+    console.log("My favorite food is " + food);
+
+}favoriteFood("fruit");
+
+// ### Task C
+
+//Create a function called `multiply` that accepts two numbers and returns the product.
+
+//### Task D
+
+//Create a function called `isEven` that accepts one number and returns whether the number is even.
+
+//---
+
+function multiply(num1, num2){
+return num1*num2;
+}
+let product = multiply(5,3);
+console.log("Product :" + product);
+
+function isEvent(num){
+    return num %2 === 0;
+}
+let number = 4;
+console.log("is" + number + "even?" + isEvent(number));
+
+//----
+//## Check for Understanding
+
+//Answer these questions in comments:
+
+//1. Why are functions useful? functions are reuable blocks of code that 
+// perform a specific task, they help to organize code and make it more midular, 
+// and they allow us to avoid repetition by encapsulating logic that can be called multiple times with different inputs.
+//2. What is a parameter? A parameter is a value the function receives.
+3//. What is the difference between `console.log()` and `return`? Prints output to the console
+// return gives back a value from a function to the caller, allowing the function to produce a result that can be used elsewhere in the code.
+//---------
+
+//## Practice 4: Use Loops
+//### Task A
+//Write a `for` loop that prints numbers 1 through 10.
+for(let i=1; i<=10; i++){
+    console.log(i);
+}
+
+//### Task B
+//Write a `for` loop that prints only even numbers from 2 to 20.
+for(let i=2; i<=20; i++){
+    if(i%2== 0){
+        console.log(i);
+    }
+}
+//### Task C
+//Write a `while` loop that prints numbers 5 down to 1.
+let j=5;
+while(j>=1){
+    console.log(j);
+    j--;
+}
+//### Task D
+//Write a loop that prints:
+//```javascript
+//"Practice makes progress"
+//five times.
+//---
+
+for(let k=0; k<5; k++){console.log("Practice makes progress");}
+
+////## Check for Understanding
+//Answer these questions in comments:
+
+//1. What is a loop used for? A loop repeats code multiple times.
+//2. When might you use a `for` loop? /It is useful when you know how many times you want to repeat something.
+//3. What could happen if a loop condition never becomes false?infinite loop, it will continue to run indefinitely, which can cause the program to crask or become unresponsive and consume system resources.
+
+//---
+
+//# Part 5: Combine Everything
+//## Mini Challenge 1: Number Checker
+//Create a function that:
+//* accepts one number
+//* uses a conditional to check whether it is positive, negative, or zero
+//* prints the result
+
+function checkNumber(num) {
+    if (num > 0) {
+        console.log("The number is positive.");
+    } else if (num < 0) {
+        console.log("The number is negative.");
+    } else {
+        console.log("The number is zero.");
+    }
+}
+
+// Test examples
+checkNumber(5);
+checkNumber(-3);
+checkNumber(0);
+
+//---
+
+//## Mini Challenge 2: Countdown Function
+//Create a function that:
+//* accepts one number
+//* uses a loop to count down from that number to 1
+//* prints each number
+function countdown(num) {
+    for (let i = num; i >= 1; i--) {
+        console.log(i);
+    }
+}
+
+// Test example
+countdown(5);
+
+//---
+
+//## Mini Challenge 3: Student Progress Checker
+//Create:
+//* a variable called `studentName`
+//* a variable called `score`
+
+//Then create a function that checks the score and prints:
+
+//* `"Excellent work"` for 90 and above
+//* `"Good job"` for 75 to 89
+//* `"Keep practicing"` below 75
+
+let studentName = "Lan Nguyen";
+let score = 85;
+
+// Function to check score
+function checkScore(name, score) {
+    console.log("Student:", name);
+
+    if (score >= 90) {
+        console.log("Excellent work");
+    } else if (score >= 75) {
+        console.log("Good job");
+    } else {
+        console.log("Keep practicing");
+    }
+}
+
+// Call function
+checkScore(studentName, score);
+//---
+
+//## Mini Challenge 4: Class Roster
+//Create an array of 5 names if you already know arrays.
+//If you do **not** know arrays yet, just create 5 separate variables.
+//Then:
+
+//* write a loop
+//* print each student name one at a time
+
+//> Bonus: If you have not learned arrays yet, skip this one or ask your instructor for support.
+// Class roster (array of 5 names)
+let students = ["Lan", "John", "Maria", "David", "Sophia"];
+
+// Loop through and print each name
+for (let i = 0; i < students.length; i++) {
+    console.log(students[i]);
+}
+//---
+
+//# Stretch Challenges
+//Complete these if you finish early.
+//### Stretch 1
+//Write a function called `gradeCalculator` that returns:
+
+//* `"A"` for 90–100
+//* `"B"` for 80–89
+//* `"C"` for 70–79
+//* `"D"` for 60–69
+//* `"F"` below 60
+
+function gradeCalculator(score) {
+    if (score >= 90 && score <= 100) {
+        return "A";
+    } else if (score >= 80) {
+        return "B";
+    } else if (score >= 70) {
+        return "C";
+    } else if (score >= 60) {
+        return "D";
+    } else {
+        return "F";
+    }
+}
+
+// Example tests
+console.log(gradeCalculator(95)); // A
+console.log(gradeCalculator(82)); // B
+console.log(gradeCalculator(74)); // C
+console.log(gradeCalculator(65)); // D
+console.log(gradeCalculator(50)); // F
+//---------
+
+//### Stretch 2
+//Write a loop that prints all numbers from 1 to 30 that are divisible by 3.
+
+for(let i=1; i<30; i++){
+    if(i%3===0){
+        console.log(i);
+    }
+}
+
+//### Stretch 3
+//Write a function that accepts a name and a number, then prints that name the number of times given.
+//### Stretch 4
+//Write a program that checks if a number is odd or even and then prints the result 10 times using a loop.
+function printName(name, times) {
+    for (let i = 0; i < times; i++) {
+        console.log(name);
+    }
+}
+
+// Example
+printName("Lan Nguyen", 3);
+
+//---
+
+function checkOddEven(num) {
+    let result;
+
+    if (num % 2 === 0) {
+        result = "Even";
+    } else {
+        result = "Odd";
+    }
+
+    for (let i = 0; i < 10; i++) {
+        console.log(result);
+    }
+}
+
+// Example
+checkOddEven(8);
+
+//-----------
+
+//# Reflection Questions
+
+//Answer these in comments at the bottom of your file:
+
+//1. Which topic felt easiest for you? yes
+//2. Which topic felt most challenging? none
+//3. How do variables, conditionals, functions, and loops work together in a program?Variable → studentScores stores data
+//Function → analyzeScores() organizes logic, Loop → goes through each score, Conditionals → decide the grade
+//Together, they turn raw data into meaningful results.
+//4. What is one question you still have about JavaScript? When should I use a function instead of writing code directly in a loop or conditional?