JavaScript Practice Questions

1. JavaScript Program to Swap the Values of Two Variables Using a Third Variable

Swapping the values of two variables is a basic operation in many programming tasks. In JavaScript, you can achieve this using a third variable.

JavaScript Code:

// Function to swap the values of two variables
function swapValues(a, b) {
  let temp = a;
  a = b;
  b = temp;
  return { a: a, b: b };
}

// Example usage
let x = 5;
let y = 10;
let swapped = swapValues(x, y);
console.log(`After swapping: x = ${swapped.a}, y = ${swapped.b}`);

In this program, we define a function swapValues() that swaps the values of two variables a and b using a third variable temp to temporarily hold one of the values. For example, if x = 5 and y = 10, after swapping, x will be 10, and y will be 5.

2. JavaScript Program to Convert Celsius to Fahrenheit

Temperature conversion is an essential task in many applications. Here, we will learn how to convert a temperature from Celsius to Fahrenheit using JavaScript.

Formula:

The formula for converting Celsius to Fahrenheit is:

F = \left( \frac{9}{5} \times C \right) + 32

Where:

• C is the temperature in Celsius
• F is the temperature in Fahrenheit

JavaScript Code:

// Function to convert Celsius to Fahrenheit
function celcToFahr(celsius) {
  return (celsius * 9/5) + 32;
}

// Example usage
let celsius = 20;
let fahrenheit = celcToFahr(celsius);
console.log(`${celsius} Celsius is equal to ${fahrenheit} Fahrenheit.`);

This function accepts a Celsius value and returns the corresponding Fahrenheit temperature. For example, if you input 20°C, the output will be 68°F.

3. JavaScript Program to Find Area and Perimeter of a Rectangle

In geometry, working with basic shapes like rectangles is common. JavaScript can help you calculate the area and perimeter of a rectangle with just a few lines of code.

Formulas:

• Area: A = \text{length} \times \text{width}
• Perimeter: P = 2 \times (\text{length} + \text{width})

JavaScript Code:

// Function to calculate area and perimeter of a rectangle
function calc(len, wid) {
  let area = len * wid;
  let perimeter = 2 * (len + wid);
  return { area: area, perimeter: perimeter };
}

// Example usage
let length = 10;
let width = 5;
let result = calc(length, width);
console.log(`Area: ${result.area}, Perimeter: ${result.perimeter}`);

This program calculates both the area and perimeter of a rectangle given its length and width. For example, if the length is 10 units and the width is 5 units, the output will be an area of 50 and a perimeter of 30.

4. JavaScript Program to Find Simple Interest

Simple interest is a common financial calculation. It’s used in various scenarios, such as calculating the interest on loans or investments. The formula for calculating simple interest is:

Formula:

\text{Simple Interest} = \frac{P \times T \times R}{100}

Where:

• P is the principal amount (initial investment or loan)
• T is the time period (in years)
• R is the rate of interest

JavaScript Code:

// Function to calculate simple interest
function calculateSimpleInterest(principal, time, rate) {
  return (principal * time * rate) / 100;
}

// Example usage
let principal = 10000;
let time = 5;  // in years
let rate = 5;  // in percentage
let interest = calculateSimpleInterest(principal, time, rate);
console.log(`The simple interest is ${interest}`);

This program calculates simple interest based on the principal, time, and interest rate. For example, if you have a principal of 10,000, a rate of 5%, and a time period of 5 years, the simple interest will be 2500.