How to check if a HashSet is empty in Kotlin

How to check if a HashSet is empty in Kotlin.

Here's a step-by-step tutorial on how to check if a HashSet is empty in Kotlin.

Create a HashSet:
- To begin, create a HashSet using the HashSet constructor. For example, you can create a HashSet of integers like this:
```
val numbers = HashSet<Int>()
```
  In this case, we've created an empty HashSet called numbers to store integers.
Check if the HashSet is empty using the isEmpty() function:
- Kotlin provides a built-in isEmpty() function that you can use to check if a HashSet is empty.
- To use it, simply call the isEmpty() function on your HashSet and store the result in a Boolean variable.
```
val isEmpty = numbers.isEmpty()
```
  Here, the isEmpty variable will be true if the HashSet is empty, and false otherwise.
Check if the HashSet is empty using the size property:
- Alternatively, you can also check if a HashSet is empty by comparing its size property to zero.
- The size property returns the number of elements in the HashSet.
```
val isEmpty = numbers.size == 0
```
  In this example, the isEmpty variable will be true if the HashSet has no elements, and false otherwise.
Use the isEmpty() function in an if statement:
- One common use case is to check if a HashSet is empty and perform certain actions based on the result.
- You can achieve this by using the isEmpty() function within an if statement.
```
if (numbers.isEmpty()) {
    // HashSet is empty
    println("HashSet is empty")
} else {
    // HashSet is not empty
    println("HashSet is not empty")
}
```
  In this example, if the HashSet numbers is empty, the program will print "HashSet is empty". Otherwise, it will print "HashSet is not empty".
Use the size property in an if statement:
- Similarly, you can also use the size property within an if statement to check if a HashSet is empty.
```
if (numbers.size == 0) {
    // HashSet is empty
    println("HashSet is empty")
} else {
    // HashSet is not empty
    println("HashSet is not empty")
}
```
  This code will have the same output as the previous example.

That's it! You now know how to check if a HashSet is empty in Kotlin. You can use either the isEmpty() function or compare the size property to zero.