Switch statement in Programming

Switch statement in programming enables the execution of different code blocks based on the value of an expression, providing a structured approach to handle multiple cases efficiently. It enhances code readability and simplifies decision-making processes, making it a valuable tool for managing program flow and facilitating branching logic in software development.

What is Switch Statement?

Switch statement is a fundamental building block in many programming languages. It allows us to efficiently handle situations where the program needs to perform different actions based on different values of a variable.

For Eg: Imagine you’re writing a program for a lift. The user selects a floor by pressing a button, and the lift needs to take the user to the selected floor. A switch statement is a great tool for such a scenario! By comparing the user’s selection with different cases, the program can execute the appropriate code.

Syntax and Structure of Switch Statement:

A switch statement typically consists of the following elements.

• Switch expression: This is an expression that is evaluated to determine which case to execute. Commonly, it’s an integer or a character variable.
• Case Statement: These statements define the different possible values the switch expression can take and the corresponding code to be executed if there’s a match.
• Case block: This block contains the code to be executed based on the value of the switch expression.
• Break statement: This statement terminates the execution of the case block once a matching case is found. Without a break, the program might continue executing code from subsequent cases.

The syntax and structure of switch-case statements are similar across languages, with slight syntactic variations. Here is a general template.

Code Snippet

switch (switch_expression) {
  case value1:
    // Code to execute if switch_expression equals value1
    break;
  case value2:
    // Code to execute if switch_expression equals value2
    break;
  // ... more cases
  default:
    // Code to execute if no matching case is found (optional)
}

Now let’s dive into the details of each of the components of a switch-case statement.

Case Statement:

Each case statement defines a possible value the switch expression can take. The syntax usually involves the case keyword followed by the constant value.

case value:
    // Code to execute when switch_expression equals value

The program checks each case statement sequentially until it finds a match with the switch expression’s value. Once a match is found, the corresponding code block is executed.

Break Statement:

The break statement is an important element within the switch block. After a matching case is executed, the break statement terminates the switch block entirely, preventing the program from accidentally falling through and executing code from subsequent cases. This is also called fallthrough behaviour.

Here’s an example to illustrate this.

// This is just a pseudo-code
switch (day) {
  case 1:
    print("Monday");
    break;
  case 2:
    print("Tuesday");
  // Without a break here, Wednesday will also be printed if day is 2!
  case 3:
    print("Wednesday");
    break;
  // ... more cases
}

In this example, if day is 2, both “Tuesday” and “Wednesday” will be printed without the break statements.

Default Statement:

The default statement in programming is a fallback option used in switch statements. It is executed when none of the case labels match the value of the expression being evaluated.

switch (expression) {
    case value1:
        // Code block to execute if expression matches value1
        break;
    case value2:
        // Code block to execute if expression matches value2
        break;
    // More cases...
    default:
        // Code block to execute if expression does not match any case
}

Switch Statement in C:

Here are the example of Switch Statement in C language:

C

#include <stdio.h>

int main()
{
    int day = 2;
    switch (day) {
    case 1:
        printf("Monday");
        break;
    case 2:
        printf("Tuesday");
        break;
    case 3:
        printf("Wednesday");
        break;
    case 4:
        printf("Thrusday");
        break;
    case 5:
        printf("Friday");
        break;
    case 6:
        printf("Saturday");
        break;
    case 7:
        printf("Sunday");
        break;
    default:
        printf("Not a valid number");
    }
    return 0;
}

Output

Tuesday

Switch Statement in C++:

Here are the example of Switch Statement in C++ language:

C++

#include <iostream>
using namespace std;

int main()
{
    int day = 2;
    switch (day) {
    case 1:
        cout << "Monday";
        break;
    case 2:
        cout << "Tuesday";
        break;
    case 3:
        cout << "Wednesday";
        break;
    case 4:
        cout << "Thursday";
        break;
    case 5:
        cout << "Friday";
        break;
    case 6:
        cout << "Saturday";
        break;
    case 7:
        cout << "Sunday";
        break;
    default:
        cout << "Not a valid number";
    }
    return 0;
}

Output

Tuesday

Switch Statement in Java:

Here are the example of Switch Statement in java language:

Java

public class DayOfWeek {
    public static void main(String[] args)
    {
        int day = 2;

        switch (day) {
        case 1:
            System.out.println("Monday");
            break;
        case 2:
            System.out.println("Tuesday");
            break;
        case 3:
            System.out.println("Wednesday");
            break;
        case 4:
            System.out.println("Thursday");
            break;
        case 5:
            System.out.println("Friday");
            break;
        case 6:
            System.out.println("Saturday");
            break;
        case 7:
            System.out.println("Sunday");
            break;
        default:
            System.out.println("Not a valid day number");
        }
    }
}

Output

Tuesday

Switch Statement in Python:

Before Python 3.10, there was no feature for Switch statement in Programming. In Python 3.10, they have included match and case statement to implement Switch Case in Programming. Instead of default: case, we write case _: and there is no need to write break statement after each case.

Python3

day = 2
match(day):
    case 1:
        print("Monday")
    case 2:
        print("Tuesday")
    case 3:
        print("Wednesday")
    case 4:
        print("Thrusday")
    case 5:
        print("Friday")
    case 6:
        print("Saturday")
    case 7:
        print("Sunday")
    case _:
        print("Not a valid number")

Switch Statement in C#:

Here are the example of Switch Statement in C# language:

C#

using System;

class DayOfWeek {
    static void Main(string[] args)
    {
        int day = 2;

        switch (day) {
        case 1:
            Console.WriteLine("Monday");
            break;
        case 2:
            Console.WriteLine("Tuesday");
            break;
        // more cases
        default:
            Console.WriteLine("Not a valid day number");
            break;
        }
    }
}

Output

Tuesday

Switch Statement in JavaScript:

Here are the example of Switch Statement in javascript language:

JavaScript

let day = 2;

switch (day) {
  case 1:
    console.log("Monday");
    break;
  case 2:
    console.log("Tuesday");
    break;
  // more cases
  default:
    console.log("Not a valid day number");
}

Output

Tuesday

Conclusion:

The switch statement in programming allows selecting different code paths based on a variable’s value, providing a structured approach for handling multiple cases efficiently. While beneficial for readability and decision-making, it’s crucial to use switch statements judiciously and explore alternative strategies for complex logic.