Operators
For operators, Kotlin divides into 4 groups:
- Arithmetic Operators
- Assignment Operators
- Comparison Operators
- Logical Operators
Arithmetic operators
These are used to perform mathematical operations.
| Operator | Description |
|---|---|
+ | Adds 2 numbers |
- | Subtracts 2 numbers |
* | Multiplies 2 numbers |
/ | Divides 2 numbers |
% | Returns division remainder |
++ | Increment the value by one |
-- | Decrease the value by one |
kotlin
fun main () {
val num1: Int = 10
val num2 = 20
println(num1 + num2) // 30
}fun main () {
val num1: Int = 10
val num2 = 20
println(num1 + num2) // 30
}kotlin
fun main () {
val num1: Int = 100
val num2 = 20
println(num1 - num2) // 80
}fun main () {
val num1: Int = 100
val num2 = 20
println(num1 - num2) // 80
}kotlin
fun main () {
val num1: Int = 3
val num2 = 8
println(num1 * num2) // 24
}fun main () {
val num1: Int = 3
val num2 = 8
println(num1 * num2) // 24
}kotlin
fun main () {
val num1: Int = 100
val num2 = 4
/*
* if you divide two numbers with decimal result
* but doesn't explicitly defined, the result
* will only show the integer value
* */
println(num1 / num2) // 25
val num3: Int = 100
val num4 = 6
// you should change the type from Int to Float/Double
// depends on your situation
val result: Float = num3.toFloat() / num4.toFloat()
println(result) // 16.666666
}fun main () {
val num1: Int = 100
val num2 = 4
/*
* if you divide two numbers with decimal result
* but doesn't explicitly defined, the result
* will only show the integer value
* */
println(num1 / num2) // 25
val num3: Int = 100
val num4 = 6
// you should change the type from Int to Float/Double
// depends on your situation
val result: Float = num3.toFloat() / num4.toFloat()
println(result) // 16.666666
}kotlin
fun main () {
val num1: Int = 10
val num2 = 2
println(num1 % num2) // 0
val num3: Int = 100
val num4 = 3
println(num3 % num4) // 1
}fun main () {
val num1: Int = 10
val num2 = 2
println(num1 % num2) // 0
val num3: Int = 100
val num4 = 3
println(num3 % num4) // 1
}kotlin
fun main () {
var num1: Int = 100
println(num1++) // 100, you expect to print first then update the value
println(++num1) // 102, you expect to update the value first then print data
// why 102? it is the result from previous increment
}fun main () {
var num1: Int = 100
println(num1++) // 100, you expect to print first then update the value
println(++num1) // 102, you expect to update the value first then print data
// why 102? it is the result from previous increment
}kotlin
fun main () {
var num1: Int = 100
println(num1--) // 100, you expect to print first then increase the value
println(--num1) // 98, you expect to increase the value first then print data
// why 98? it is the result from previous decrement
}fun main () {
var num1: Int = 100
println(num1--) // 100, you expect to print first then increase the value
println(--num1) // 98, you expect to increase the value first then print data
// why 98? it is the result from previous decrement
}Assignment Operators
If you want to reassign the value, don't forget to use var instead of val
| Operator |
|---|
= |
+= |
-= |
*= |
/= |
%= |
For example
kotlin
fun main() {
var initNum = 10
initNum += 5
println(initNum) // 15
initNum -= 3
println(initNum) // 12
initNum *= 5
println(initNum) // 60
initNum /= 6
println(initNum) // 10
initNum %= 2
println(initNum) // 0
}fun main() {
var initNum = 10
initNum += 5
println(initNum) // 15
initNum -= 3
println(initNum) // 12
initNum *= 5
println(initNum) // 60
initNum /= 6
println(initNum) // 10
initNum %= 2
println(initNum) // 0
}Comparison Operators
It will return the Boolean value
| Operator | Description |
|---|---|
== | Equal to |
!= | Not equal to |
> | Greater than |
< | Less than |
>= | Greater than or equal to |
<= | Less than or equal to |
Logical Operators
It will return the Boolean value
| Operator | Description |
|---|---|
&& | Combine 2 logical expressions, return true if both expressions valid |
|| | Combine 2 logical expressions, return true if one of the expressions valid |
! | Reverse value, true -> false, false -> true |