JavaScript Switch Case
In JavaScript, a switch statement allows you to select one of many code blocks to be executed based on a specific value. It is typically used when you need to compare a single expression (like a variable) against several possible values.
Basic Structure:
switch (expression) {
case value1:
// code to be executed;
break;
case value2:
// code to be executed;
break;
// more cases…
default:
// code to be executed if no cases match;
break;
}
Scenario: Pricing System Using JavaScript switch
In this scenario, we simulate a pricing system using a switch statement. The program will take the name of a car (Mustang, Ford, or another) and output the corresponding price. If no car matches, it will return “Invalid car name.”
Scenario 1: When car = "Ford"
let car = “Ford”;
switch (car) {
case “Mustang”:
console.log(“Price is 1cr”);
break;
case “Ford”:
console.log(“Price is 50 Lakhs”);
break;
default:
console.log(“Invalid car”);
break;
}
Output:
Code Explanation:
Variable Declaration (let car = “Ford”;):
• In JavaScript, we declare the variable car using let, which holds the string value “Ford”.
• let is used for variable declaration (it allows reassignment and has block scope)
Switch Statement:
• The switch statement is used to compare the value of the variable car to different case labels.
• The expression inside the switch is car, and the switch checks which case matches the value of car
case “Mustang”:
• The first case checks if a car is equal to the string “Mustang”.
• Since the car is “Ford”, this case is skipped.
case “Ford”:
• The second case checks if the car is equal to the string “Ford”.
• This matches because the car is indeed “Ford”.
• The code inside this case block is executed, so it prints “Price is 50Lakhs” to the console.
Scenario 2: When car = "Mustang"
let car = “Mustang”;
switch (car) {
case “Mustang”:
console.log(“Price is 1cr”);
break;
case “Ford”:
console.log(“Price is 50 Lakhs”);
break;
default:
console.log(“Invalid car”);
break;
}
Output:
Code Explanation:
Variable Declaration (let car = “Mustang”;):
• Here, we declare the variable car and set it to the string “Mustang”.
• let is used for variable declaration (it allows reassignment and has block scope)
Switch Statement:
• The switch expression is a car, and the statement evaluates which case matches the value of the car.
• Since the car is “Mustang”, the switch will start checking each case
case “Mustang”:case “Mustang”:
• The first case checks if car is equal to “Mustang”.
• Since car is indeed “Mustang”, this case block will execute , so it prints “Price is 1cr” to the console.
Scenario 3: When car = "Ferrari"
let car = “Ferrari”;
switch (car) {
case “Mustang”:
console.log(“Price is 1cr”);
break;
case “Ford”:
console.log(“Price is 50 Lakhs”);
break;
default:
console.log(“Invalid car”);
break;
}
Output:
Code Explanation:
Variable Declaration (let car = “Ferrari”;):
• Here, we declare the variable car and set it to the string ” Ferrari “.
• let is used for variable declaration (it allows reassignment and has block scope)
Switch Statement:
• The switch expression is a car, and the statement evaluates which case matches the value of the car.
• Since the car is ” Ferrari “, the switch will start checking each case
Default Case:
• If none of the case labels match the value of the car, the default case is executed.
• Since the car is ” Ferrari “, which doesn’t match either “Mustang” or “Ford”, the default case is triggered.
• The message “Invalid car” will be printed on the console.
Course Video in Hindi
YouTube Reference:
Practice Scenarios
1. Identify Month Name:
Objective: Given a month number (1 to 12), print the corresponding month name using a switch statement.
Input: month = 5
Output:
2.Simple Calculator (Addition, Subtraction, Multiplication)
Objective: Perform basic arithmetic operations based on user input using a switch-case.
Input: operator = “+”, a = 5, b = 3
Output:
3.Determine Day Type
Objective: Given a day of the week number (1-7), check if it’s a weekend or weekday.
Input: day = 6
Output:
4.Check Grade
Objective: Based on a grade letter (A, B, C, D, F), print the description of the grade.
Input: grade = “B”
Output:
Input: grade = “A”
Output:
Input: grade = “C”
Output:
5.Calculate Shipping Cost:
Objective: Based on the country name, calculate the shipping cost
Input: country = “Canada”
Output:
6.Day of the Week:
Objective: Use a switch statement to display the corresponding day of the week based on a number (1 for Monday, 2 for Tuesday, etc.).
Input: day = 3;
Output:
7.Traffic Light:
Objective: Display the action to take based on the traffic light color.
Input: color = “red”;
Output:
8.Vowel Check:
Objective: Check if a character is a vowel or consonant.
Input: char = “e”;
Output:
Input: char = “f”;
9.Age Group:
Objective: Determine the age group based on age.
Input: age = 25;
Output:
Input: age = 7;
Output:
Input: age = 70;
Output:
10.Grade Evaluation
Objective: Use a switch statement to display a grade based on a score.
Input: score = 85;
Output:
Input: score = 92;
Output:
Input: score = 65;
Output:
