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How to round a decimal number to a specific number of decimal places in Kotlin

How to round a decimal number to a specific number of decimal places in Kotlin.

Here's a step-by-step tutorial on how to round a decimal number to a specific number of decimal places in Kotlin:

Step 1: Import the necessary classes​

To perform rounding operations, we need to import the java.math.BigDecimal class. Add the following import statement at the top of your Kotlin file:

import java.math.BigDecimal

Step 2: Define the decimal number​

Next, define the decimal number that you want to round. You can assign it to a variable of type BigDecimal. For example, let's say we want to round the number 3.14159 to 2 decimal places:

val number = BigDecimal("3.14159")

Step 3: Specify the number of decimal places to round​

Decide on the number of decimal places to which you want to round the number. In this example, we want to round to 2 decimal places.

val decimalPlaces = 2

Step 4: Perform rounding​

To round the decimal number, we can use the setScale method provided by the BigDecimal class. This method takes two arguments: the first argument is the desired number of decimal places, and the second argument is the rounding mode.

In this example, we want to round the number to 2 decimal places and use the ROUND_HALF_UP rounding mode. Here's how you can perform the rounding:

val roundedNumber = number.setScale(decimalPlaces, BigDecimal.ROUND_HALF_UP)

Step 5: Display the rounded number​

Finally, you can display the rounded number by printing it using the println function:

println("Rounded number: $roundedNumber")

Here's the complete code:

import java.math.BigDecimal

fun main() {
    val number = BigDecimal("3.14159")
    val decimalPlaces = 2
    val roundedNumber = number.setScale(decimalPlaces, BigDecimal.ROUND_HALF_UP)
    println("Rounded number: $roundedNumber")
}

When you run the code, it will output:

Rounded number: 3.14

That's it! You have successfully rounded a decimal number to a specific number of decimal places in Kotlin.