Multiply and divide
- Kotlin course
- Beginner
- Lesson 21/116
- 6 min
Add multiplication, division and the divide-by-zero check.
multiply and divide
Let's add multiplication and division to the calculator. multiply computes a * b. divide computes a / b; but when b == 0 it returns 0 — because integer division by zero throws ArithmeticException in Kotlin.
fun multiply(a: Int, b: Int): Int {
return a * b
}
fun divide(a: Int, b: Int): Int {
if (b == 0) {
return 0
}
return a / b
}Practice Add multiply and divide
Add fun multiply(a: Int, b: Int): Int { return a * b } and fun divide(a: Int, b: Int): Int { if (b == 0) { return 0 }; return a / b } to the existing code. Inside main, add println(multiply(5, 3)) and println(divide(10, 2)); keep existing calls.
Starter code
fun add(a: Int, b: Int): Int {
return a + b
}
fun subtract(a: Int, b: Int): Int {
return a - b
}
fun main() {
println("Calculator")
println(add(5, 3))
println(subtract(5, 3))
}Sample solution
fun add(a: Int, b: Int): Int {
return a + b
}
fun subtract(a: Int, b: Int): Int {
return a - b
}
fun multiply(a: Int, b: Int): Int {
return a * b
}
fun divide(a: Int, b: Int): Int {
if (b == 0) {
return 0
}
return a / b
}
fun main() {
println("Calculator")
println(add(5, 3))
println(subtract(5, 3))
println(multiply(5, 3))
println(divide(10, 2))
}Expected output
Calculator 8 2 15 5
Division by zero
Integer division by zero (a / 0) throws ArithmeticException at runtime in Kotlin. So the divide function checks with if (b == 0) and safely returns 0.
Such preventive checks are especially important when working with user input. A user can enter zero; the program must not crash.
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 multiply return
fun multiply(a: Int, b: Int): Int {
return a ____ b
}fun multiply(a: Int, b: Int): Int {
return a * b
}Explanation: multiply performs multiplication.
2 Match the operations
| Term | Meaning |
|---|---|
add |
+ |
subtract |
- |
multiply |
* |
divide |
/ |
3 What does `divide(10, 0)` return with this divide function?
- 0 Correct answer
- 10
- It throws an error
- 1
Explanation: The divide function checks for zero and returns 0.