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1. Introduction

In Kotlin, val and const are both used to declare variables that cannot be reassigned after initialization, but they have distinct characteristics and uses. The val keyword declares a read-only property or local variable. Meanwhile, const is used to define compile-time constants, meaning the value of a const variable is known at compile time and cannot be changed.

2. Key Points

1. Mutability: Both val and const are immutable, but val can have a custom getter with varying values.

2. Initialization: const must be initialized with a value known at compile time, val can be initialized with a runtime expression.

3. Usage Scope: const can only be used at the top level or in an object declaration, not in a class. val can be used anywhere.

4. Type Restrictions: const only allows primitives and String types, while val has no such restriction.

3. Differences

Characteristic	Val	Const
Mutability	Immutable with a custom getter	Immutable, no custom getter
Initialization	Runtime expression	Compile-time expression
Usage Scope	Anywhere	Top-level or in an object
Type Restrictions	No restrictions	Primitives and String

4. Example

// Example of Val
val pi: Double
    get() = 3.14

// Example of Const
const val MAX_COUNT = 100

Output:

Val Output:
pi will return 3.14 when accessed
Const Output:
MAX_COUNT will always be 100

Explanation:

1. pi is a val with a custom getter, allowing for complex logic. Its value is determined at runtime.

2. MAX_COUNT is a const, which means its value is set at compile time and cannot be changed.

5. When to use?

- Use val for read-only properties that might require complex initialization or a custom getter.

- Use const for defining constants that are primitives or Strings, whose value you know at compile time and that are not tied to a class instance.

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Difference Between val and const in Kotlin

1. Introduction

2. Key Points

3. Differences

4. Example

Output:

Explanation:

5. When to use?

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