Kotlin Unsigned Int

Kotlin is a statically-typed programming language that runs on the Java Virtual Machine (JVM). It is a modern language that was designed to be more expressive, concise, and safe than Java.

One of the features of Kotlin is its support for unsigned integers, which are a type of integer that can only represent positive values. In this article, we will explore how to use unsigned integers in Kotlin.

Unsigned Integers in Kotlin

To declare an unsigned integer in Kotlin, we use the U suffix. This tells the compiler that we are declaring an unsigned integer value. For example:

val x: UInt = 5U

This declares a variable x of type UInt with a value of 5.

We can also perform arithmetic operations on unsigned integers, just like regular integers. However, we need to use the corresponding unsigned operator. For example:

val x: UInt = 5U
val y: UInt = 3U

val z = x + y   // z = 8U
val w = x - y   // w = 2U
val q = x * y   // q = 15U
val r = x / y   // r = 1U

Notice that we used the +, -, *, and / operators, but we appended the U suffix to the operands x and y.

Unsigned Overflow

One important thing to note about unsigned integers is that they can overflow. That is, if we add two unsigned integers and the result is greater than the maximum value that the UInt type can represent, the result will "wrap around" back to the minimum value.

For example, the UInt type can represent integers from 0 to 4294967295. If we add 4294967294U to 3U, we get 4294967297U. However, because this value is greater than the maximum value that UInt can represent, the result will "wrap around" back to 2. This is known as integer overflow.

To avoid integer overflow, we can use the U.compareTo method to check if the result of an arithmetic operation is greater than the maximum value that the UInt type can represent:

val x: UInt = 4294967294U
val y: UInt = 3U

val res = x + y

if (res.compareTo(x) < 0) {
    println("Overflow!")
} else {
    println(res)
}

This code adds x and y, and then uses the compareTo method to check if the result is less than x. If it is, we print "Overflow!".

Conclusion

Unsigned integers are a useful addition to the Kotlin language, and can help us write faster and more efficient code. However, we need to be careful when working with unsigned integers to avoid integer overflow.