Try-catch as an expression in Kotlin - Mini Project: Build & Apply

Try-catch as an expression

📖 Scenario: Imagine you are writing a small Kotlin program that tries to convert user input into a number. Sometimes the input might not be a valid number, so you want to handle that error smoothly.

🎯 Goal: You will build a Kotlin program that uses try-catch as an expression to safely convert a string to an integer. If the conversion fails, it will return a default value.

📋 What You'll Learn

Create a variable with a string that might not be a number

Create a default integer value for fallback

Use try-catch as an expression to convert the string to an integer or use the default

Print the final integer value

💡 Why This Matters

🌍 Real World

Handling user input or data from files where the format might be incorrect is common. Using try-catch as an expression helps keep code clean and safe.

💼 Career

Many Kotlin jobs require safe error handling and working with user input or external data. This skill is essential for writing robust applications.

1

Create the input string

Create a variable called input and set it to the string "abc123".

Kotlin

# Create a variable called input and set it to "abc123"
# Your code here

Need a hint?

Use val input = "abc123" to create the string variable.

2

Create the default fallback value

Create a variable called defaultValue and set it to the integer 0.

Kotlin

val input = "abc123"
# Create a variable called defaultValue and set it to 0
# Your code here

Need a hint?

Use val defaultValue = 0 to create the fallback integer.

3

Use try-catch as an expression to convert input

Create a variable called number and set it to the result of a try-catch expression that tries to convert input to an integer using input.toInt(). If an exception occurs, return defaultValue.

Kotlin

val input = "abc123"
val defaultValue = 0
# Use try-catch as an expression to convert input to an integer or use defaultValue
# Your code here

Need a hint?

Use val number = try { input.toInt() } catch (e: Exception) { defaultValue } to handle conversion safely.

4

Print the result

Write a println statement to display the value of number.

Kotlin

val input = "abc123"
val defaultValue = 0
val number = try {
    input.toInt()
} catch (e: Exception) {
    defaultValue
}
# Print the value of number
# Your code here

Need a hint?

Use println(number) to show the final integer.