task.js

//* **************************************************************
//* Day 5 : Functions
//* **************************************************************


//* Difference between function declaration and function expression

    //* Function Declaration : 
    ```
    function functionName(parameters) { 
        // function body 
    }
    ```

    //* Function Expression : 
    ```
    const/let/var functionName = function(parameters) { 
        // function body 
    }
    ```

//* Difference between normal function and arrow function

    //* Normal Function : 
    ```
    function functionName(parameters) { 
        // Function body 
    }
    ```
    
    //* Arrow Function : 
    ```
    const/let/var functionName = (parameters) => { 
        // function body 
    }
    ```


//* **************************************************************
//* Activity 1: Function Declaration
//* **************************************************************

//* Task 1: Write a function to check if a number is even or odd and log the result to the console.
function checkEvenOdd(num) {
    if(num % 2 === 0)
        console.log(`${num} is a even number`);
    else
        console.log(`${num} is a odd number`);
}
// Function call
checkEvenOdd(5);    // Output -> 5 is a odd number
checkEvenOdd(10);   // Output -> 10 is a even number


//* Task 2: Write a function to calculate the square of a number and return the result.
function findSquare(num) {
    return num * num;
}

// Printing the square of a number
let result = findSquare(5);
console.log(`Square of 5 is : ${result}`);      // Output -> Square of 5 is : 25


//* **************************************************************
//* Activity 2: Function Expression
//* **************************************************************

//* Task 3: Write a function expression to find the maximum of two numbers and log the result to the console.
const findmax = function (num1, num2) {
    if(num1 > num2) {
        console.log(`${num1} is greater than ${num2}`);
    }
    else {
        console.log(`${num2} is greater than ${num1}`);
    }
}

// Function call
findmax(5, 7);      // Output -> 7 is greater than 5
findmax(15, 7);     // Output -> 15 is greater than 7


//* Task 4: Write a function expression to concatenate two strings and return the result.
const concatination = function(firstName, lastName) {
    return firstName + ' ' + lastName;
}

// Function call
const fullName = concatination('Suraj', 'Adhikari');
console.log(`Full name is : ${fullName}`);      // Output -> Full name is : Suraj Adhikari


//* **************************************************************
//* Activity 3: Arrow Functions
//* **************************************************************

//* Task 5: Write an arrow function to calculate the sum of two numbers and return the result.
//* Method 1:
const addition = (num1, num2) => {
    return num1 + num2;
}
// Function call
const sum = addition(5, 10);
console.log(`Sum is : ${sum}`);                 // Output -> Sum is : 15

// Function call
console.log(addition(10, 20));                  // Output -> 30


//* Method 2:
const addTwoNumbers = (num1, num2) => num1 + num2;      // Implicit Return

//Function call
console.log(addTwoNumbers(50, 55));             // Output -> 105


//* Method 3:
const addTwoNums = (num1, num2) => ( num1 + num2 );

// Function Call
console.log(addTwoNumbers(150, 110));           // Output -> 260


//* Task 6: Write an arrow function to check if a string contains a specific character and return a boolean value.
const isContain = (word, char) => {
    if(word.includes(char))
        return true;
    else
        return false;
}
const answer = isContain('Suraj', 'a');
console.log(answer);                                // Output -> true


//* **************************************************************
//* Activity 4: Function Parameters and Default Values
//* **************************************************************

//* Task 7: Write a function that takes two parameters and returns their product. Provide a default value for the second parameter.
const product = (num1, num2 = 15) => {              // Arrow Function
    return num1 * num2;
}
console.log(`Product is : ${product(10)}`);         // Output -> Product is : 150
console.log(`Product is : ${product(10, 12)}`);     // Output -> Product is : 120


//* Task 8: Write a function that takes a person's name and age and returns a greeting message. Provide a default value for the age.
const greeting = (name, age = 20) => {
    return `Hello! ${name}, Now you're ${age} years old.`;
}
console.log(greeting('Suraj'));                     // Output -> Hello! Suraj, Now you're 20 years old. 


//* **************************************************************
//* Activity 5: Higher Order Functions
//* **************************************************************

//* Task 9: Write a higher-order function that takes a function and a number, and calls the function that many times.
function callMyname() {
    console.log(`Suraj`);
}

// Define a higher-order function that takes a function and a number as arguments
function highOrderFunction(func, num){
    for(let i = 0; i < num; i++) {
        func();
    }
}

// Call the higher-order function, passing the callMyName function as an argument
highOrderFunction(callMyname, 5);       // This will call callMyname 5 times


//* Task 10: Write a higher-order function that takes two functions and a value, applies the first function to the value, and then applies the second function to the result.

// Define an arrow function that adds 5 to a number and return their result.
const add = (num) => num + 5;

// Define an arrow function that multiplies a number by 3 and return their result.
const multiply = (num) => num * 3;

// Define a higher-order function that takes two functions and a number as arguments
function highOrderFunction(fun1, fun2, num) {
    const result1 = fun1(num);          // Apply the first function to the number
    const result2 = fun2(result1);      // Apply the second function to the result of the first function
    return result2;                     // Return the final result

    // Shorthand of above code : return fun2(fun1(num));
}
// Call the higher-order function, passing the add and multiply functions and a number
const output = highOrderFunction(add, multiply, 10);
console.log(output);                    // Output -> 45 (since (10 + 5) * 3 = 45)


//* **************************************************************
//* Feature Request:
//* **************************************************************

//* Feature 1: Write a script that includes a function to check if a number is even or odd and logs the result.
//* Method 1: Using Normal Function
function checkOddEven(num) {
    if(num % 2 === 0)
        console.log(`${num} is even number`);
    else 
        console.log(`${num} is odd number`);
}
// Function call
checkOddEven(20);       // Output -> 20 is even number
checkOddEven(15);       // Output -> 15 is odd number


//* Method 2: Using Arrow Function
const findOddEven = (num) => {
    if(num % 2 === 0)
        console.log(`${num} is even number`);
    else 
        console.log(`${num} is odd number`);
}
// Function call
findOddEven(5);         // Output -> 5 is odd number
findOddEven(50);        // Output -> 50 is even number


//* Method 3: Also Using Arrow Function
const findEvenOdd = (num) => num % 2 === 0 ? `${num} is even number` : `${num} is odd number`;      // Implicit (Direct) Return
// Function call
console.log(findEvenOdd(13));       // Output -> 13 is odd number       
console.log(findEvenOdd(30));       // Output -> 30 is even number


//* Feature 2: Create a script that includes a function to calculate the square of a number and returns the result.
//* Method 1: Using Normal Function
function calculateSquare(num) {
    return num * num;
}
// Function call
const square = calculateSquare(5);
console.log(`5 Square is : ${square}`);     // Output -> 5 Square is : 25   


//* Method 2: Using Arrow Function
const findSquare = (num) => {
    return num * num;
}
// Function call
const ans = findSquare(11);
console.log(`11 Square is : ${ans}`);     // Output -> 11 Square is : 121


//* Method 3: Also Using Arrow Function
const calcSquare = (num) => num * num;
// Function call
console.log(calcSquare(20));                // Output -> 400


//* Feature 3: Write a script that includes a higher-order function to apply a given function multiple times.
// Define an arrow function 'message' that logs a message to the console
const message = (value) => console.log(`${value}, everyone!`);

// Define a higher-order function 'highOrderFunction' that takes a function 'func' and a number 'num' as arguments
function highOrderFunction(func, num) {
    for(let i = 0; i < num; i++) {
        func('Hello');          // Call the function 'func' with the argument 'Hello'
    }
}

// Call 'highOrderFunction' with 'message' as the function argument and 5 as the number of times to call it
highOrderFunction(message, 5);


//* **************************************************************
//* Achievement:
//* **************************************************************

//* By the end of these activities, you will:
//* • Understand and define functions using function declarations, expressions, and arrow functions.
//* • Use function parameters and default values effectively.
//* • Create and utilize higher-order functions.
//* • Apply functions to solve common problems and perform calculations.
//* • Enhance code reusability and organization using functions.