Infix functions for readable calls in Kotlin - Mini Project: Build & Apply

Infix functions for readable calls

📖 Scenario: Imagine you are building a simple calculator app that can add numbers in a way that reads like a sentence. You want to make your code easy to read and understand, just like a natural language sentence.

🎯 Goal: You will create an infix function in Kotlin to add two numbers with a readable call style, then use it to add two numbers and print the result.

📋 What You'll Learn

Create a class called Calculator with a property value of type Int

Add an infix function called add inside Calculator that takes another Calculator and returns a new Calculator with the sum of the two values

Create two Calculator objects with values 10 and 5

Use the add function in infix style to add the two objects

Print the value of the result

💡 Why This Matters

🌍 Real World

Infix functions make code easier to read, like writing sentences. This helps when building apps that do calculations or combine data.

💼 Career

Understanding infix functions is useful for Kotlin developers to write clean, readable code in Android apps and backend services.

1

Create the Calculator class with a value property

Create a class called Calculator with a property value of type Int. Initialize it using the primary constructor.

Kotlin

class Calculator(val value: Int) {
    // Your code here
}

Need a hint?

Use Kotlin's primary constructor syntax to create the class with a property.

2

Add an infix add function to Calculator

Inside the Calculator class, add an infix function called add that takes another Calculator as a parameter named other. It should return a new Calculator with the sum of this.value and other.value.

Kotlin

class Calculator(val value: Int) {
    // Add infix function add here
    // Your code here
}

Need a hint?

Use the keyword 'infix' before the function and return a new Calculator with summed values.

3

Create two Calculator objects and add them using infix

Create two Calculator objects named calc1 with value 10 and calc2 with value 5. Then create a new Calculator called result by adding calc1 and calc2 using the infix add function.

Kotlin

class Calculator(val value: Int) {
    infix fun add(other: Calculator): Calculator {
        return Calculator(this.value + other.value)
    }
}

// Create calc1 and calc2
// Use infix add to create result
// Your code here

Need a hint?

Create objects with the given values and use the infix function without dot or parentheses.

4

Print the value of the result

Write a println statement to print the value property of the result object.

Kotlin

class Calculator(val value: Int) {
    infix fun add(other: Calculator): Calculator {
        return Calculator(this.value + other.value)
    }
}

val calc1 = Calculator(10)
val calc2 = Calculator(5)
val result = calc1 add calc2

// Print the value of result
// Your code here

Need a hint?

Use println(result.value) to show the sum.