Exercise: Pretty time display
Implement the secondsToPrettyTime function that takes an integer number of seconds and returns a string representation of the time in the following format: "X h Y min Z sec", where X, Y, and Z are the number of hours, minutes, and seconds respectively. If a value is zero, return "Now". If the input is negative, return "Invalid input".
fun secondsToPrettyTime(seconds: Int): String {
return ""
}
println(secondsToPrettyTime(-1)) // Invalid input
println(secondsToPrettyTime(0)) // Now
println(secondsToPrettyTime(45)) // 45 sec
println(secondsToPrettyTime(60)) // 1 min
println(secondsToPrettyTime(150)) // 2 min 30 sec
println(secondsToPrettyTime(1410)) // 23 min 30 sec
println(secondsToPrettyTime(60 * 60)) // 1 h
println(secondsToPrettyTime(3665)) // 1 h 1 min 5 sec
This problem can either be solved in the below playground or you can clone kotlin-exercises project and solve it locally. In the project, you can find code template for this exercise in essentials/conditions/PrettyTime.kt. You can find there starting code, example usage and unit tests.
Hint: You can use trim function on a string to remove leading and trailing whitespace characters.
Once you are done with the exercise, you can check your solution here.
import org.junit.Test
import kotlin.test.assertEquals
fun secondsToPrettyTime(seconds: Int): String {
return ""
}
fun main() {
println(secondsToPrettyTime(-1)) // Invalid input
println(secondsToPrettyTime(0)) // Now
println(secondsToPrettyTime(45)) // 45 sec
println(secondsToPrettyTime(60)) // 1 min
println(secondsToPrettyTime(150)) // 2 min 30 sec
println(secondsToPrettyTime(1410)) // 23 min 30 sec
println(secondsToPrettyTime(60 * 60)) // 1 h
println(secondsToPrettyTime(3665)) // 1 h 1 min 5 sec
}
class PrettyTimeTest {
@Test
fun testNegativeSeconds() {
val seconds = -1
val expected = "Invalid input"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testOnlySeconds() {
val seconds = 45
val expected = "45 sec"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testOnlyMinutes() {
val seconds = 60
val expected = "1 min"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testMinutesAndSeconds() {
val seconds = 150
val expected = "2 min 30 sec"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testMinutesAndSecondsWithRemainder() {
val seconds = 1410
val expected = "23 min 30 sec"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testOnlyHours() {
val seconds = 3600
val expected = "1 h"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testHoursMinutesAndSeconds() {
val seconds = 3665
val expected = "1 h 1 min 5 sec"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testZeroSeconds() {
val seconds = 0
val expected = "Now"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testHoursMinutesSecondsWithZeroMinutes() {
val seconds = 3605
val expected = "1 h 5 sec"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testHoursMinutesWithZeroSeconds() {
val seconds = 7200
val expected = "2 h"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testMinutesSecondsWithZeroHours() {
val seconds = 150
val expected = "2 min 30 sec"
assertEquals(expected, secondsToPrettyTime(seconds))
}
@Test
fun testLargeValue() {
val seconds = 123456789
val expected = "34293 h 33 min 9 sec"
assertEquals(expected, secondsToPrettyTime(seconds))
}
}
Marcin Moskala is a highly experienced developer and Kotlin instructor as the founder of Kt. Academy, an official JetBrains partner specializing in Kotlin training, Google Developers Expert, known for his significant contributions to the Kotlin community. Moskala is the author of several widely recognized books, including "Effective Kotlin," "Kotlin Coroutines," "Functional Kotlin," "Advanced Kotlin," "Kotlin Essentials," and "Android Development with Kotlin."
Beyond his literary achievements, Moskala is the author of the largest Medium publication dedicated to Kotlin. As a respected speaker, he has been invited to share his insights at numerous programming conferences, including events such as Droidcon and the prestigious Kotlin Conf, the premier conference dedicated to the Kotlin programming language.
