JavaScript Basics - Exercise 4

The comparison should include the boundary value when the exercise says “60 or more.” Store the result in a clear condition so changing the marks immediately changes the output.

javascript

let marks = 59;
if (marks > 60) {
    console.log("Pass");
} else {
    console.log("Fail");
}

//using ternary operator
marks > 60 ? console.log("Pass") : console.log("Fail");

The modulo operator returns the remainder after division by two. Both numbers must have a remainder of one for the “both odd” branch to run.

javascript

let num = 35;
let num2 = 34;
if (num % 2 === 1 && num2 % 2 === 1) {
    console.log("Odd");
} else {
    console.log("Even");
}

Assignment happens from left to right, so each value is replaced before the next assignment runs. The final line demonstrates why the original value of a is used for d.

javascript

/*
a = b 
b = c
c = d
d = a*/

let a = 10;
let b = 20;
let c = 30;
let d = 40;
a = b; //a=20, b=20, c=30, d=40
b = c; //a=20, b=30, c=30, d=40
c = d; //a=20, b=30, c=40, d=40
d = a; //a=20, b=30, c=40, d=20
console.log(a, b, c, d); //20 30 40 20

Comments document intent for people reading the program and are ignored during execution. Use // for a line and /* ... */ for a block.

Comments are used to explain code and make it more readable. They are ignored by the JavaScript engine. Single-line comments use // and multi-line comments use /* */.

A number is odd when dividing it by two leaves a non-zero remainder. The condition below prints “Yes” only for odd values.

javascript

let num = 35;
                    if (num % 2 !== 0) {
                      console.log("Yes");
} else {
                      console.log("No");
                    }

A number divisible by both 10 and 5 must have a remainder of zero for both checks. Checking both conditions makes the requirement explicit and easy to change.

javascript

let num = 60;
if (num % 10 === 0 && num % 5 === 0) {
    console.log("Yes");
} else {
    console.log("No");
}

Instead of guessing the input, compare the product directly with 100. This keeps the condition readable and makes the “Yes” branch run only for the correct value.

javascript

let num = 5;
if (num * 20 === 100) {
    console.log("Yes");
} else {
    console.log("No");
}

Calculate the percentage from the earned marks and the total marks before comparing it with 70. This works even when the total changes from 1000 to another value.

javascript

let marks = 880;
let totalMarks = 1000;
let percentage = (marks / totalMarks) * 100;
if (percentage > 70) {
    console.log("Pass");
} else {
    console.log("Fail");
}

This example treats ages greater than 21 as adults, exactly as the question specifies. Change age to test both branches of the condition.

javascript

let age = 25;
                    if (age > 21) {
                      console.log("Adult");
                    } else {
                      console.log("Minor");
                    }

A ternary expression is a compact replacement for a simple two-branch if statement. Put the condition first, then the true result, followed by the false result.

javascript


// if-else solution
if (condition) {
    // code block for true condition
} else {
    // code block for false condition
}

// ternary operator solution
condition ? trueBlock : falseBlock;