Difference Between switch-case and if-else Statement in Java

1. Introduction

In Java, switch-case and if-else are control flow statements that allow the execution of different code blocks based on certain conditions. The switch-case statement selects one of many code blocks to be executed by comparing the value of a variable against a list of case values. if-else, on the other hand, evaluates boolean expressions and executes a code block based on the result of that evaluation.

2. Key Points

1. switch-case is typically used when comparing a single variable to a series of constants.

2. if-else can evaluate complex boolean expressions involving multiple variables.

3. switch-case can improve readability when there are many values to compare and the logic for each case is brief.

4. if-else provides more flexibility as conditions are not limited to constant expressions.

3. Differences

switch-case	if-else
The switch-case evaluates a single variable or expression once and compares it against multiple possible matches.	The if-else evaluates each condition in sequence until it finds one that is true.
It can be used with the byte, short, char, int, String (since Java 7), and enum types.	It can be used with any type that can be evaluated to a boolean expression, offering more flexibility.
Ideal for scenarios where a variable or expression is being tested against multiple constants.	Better suited for conditions that involve ranges or unique expressions.
Cannot directly evaluate conditions (greater than, less than), only equality.	Can evaluate various conditions, including equality, relational, and logical operations.
The syntax is more structured, making the code cleaner and easier to read when dealing with multiple constants.	It can become unwieldy with nested conditions, making the code harder to read and maintain.
The default case is executed if none of the cases matches the expression.	An else block (though optional) can execute code when none of the conditions are true.
More flexible than if-else statements since it only works with constants and enums.	Provides greater flexibility in testing various conditions and combining them with logical operators.

4. Example

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

        // Using switch-case
        System.out.println("Using switch-case:");
        switch (number) {
            case 1:
                System.out.println("One");
                break;
            case 2:
                System.out.println("Two");
                break;
            case 3:
                System.out.println("Three");
                break;
            default:
                System.out.println("Other");
        }

        // Using if-else
        System.out.println("\nUsing if-else:");
        if (number == 1) {
            System.out.println("One");
        } else if (number == 2) {
            System.out.println("Two");
        } else if (number == 3) {
            System.out.println("Three");
        } else {
            System.out.println("Other");
        }
    }
}

Output:

Using switch-case:
Two
Using if-else:
Two

Explanation:

1. The switch case cleanly separates the logic for each case, making it easy to see all the possible values against which the number can be compared.

2. The if-else statements are sequentially evaluated, which means that the boolean expressions are checked one by one until a true condition is found or the else block is reached.

5. When to use?

Use the switch case when you have a variable that can equal a large set of known values and want to execute different logic depending on which value it equals.

Use if-else when evaluating more complex conditions or when dealing with ranges of values that cannot be easily handled by switch-case.