Kotlin Operators

Operators are the special symbols that perform different operation on operands. For example + and – are operators that perform addition and subtraction respectively. Like Java, Kotlin contains different kinds of operators. 

• Arithmetic operator
• Relation operator
• Assignment operator
• Unary operator
• Logical operator
• Bitwise operator 
  

Arithmetic Operators –

Operators	Meaning	Expression	Translate to
+	Addition	a + b	a.plus(b)
–	Subtraction	a – b	a.minus(b)
*	Multiplication	a * b	a.times(b)
/	Division	a / b	a.div(b)
%	Modulus	a % b	a.rem(b)

Kotlin

fun main(args: Array<String>)
{
    var a = 20 var b = 4 println("a + b = " + (a + b))
        println("a - b = " + (a - b))
        println("a * b = " + (a.times(b)))
        println("a / b = " + (a / b))
        println("a % b = " + (a.rem(b)))
}

Output:

a + b = 24
a - b = 16
a * b = 80
a / b = 5
a % b = 0

Relational Operators –

Operators	Meaning	Expression	Translate to
>	greater than	a > b	a.compareTo(b) > 0
<	less than	a < b	a.compareTo(b) < 0
>=	greater than or equal to	a >= b	a.compareTo(b) >= 0
<=	less than or equal to	a <= b	a.compareTo(b) <= 0
==	is equal to	a == b	a?.equals(b) ?: (b === null)
!=	not equal to	a != b	!(a?.equals(b) ?: (b === null)) > 0

Kotlin

fun main(args: Array<String>)
{
    var c = 30
    var d = 40
    println("c > d = "+(c>d))
    println("c < d = "+(c.compareTo(d) < 0))
    println("c >= d = "+(c>=d))
    println("c <= d = "+(c.compareTo(d) <= 0))
    println("c == d = "+(c==d))
    println("c != d = "+(!(c?.equals(d) ?: (d === null))))
}

Output:

c > d = false
c < d = true
c >= d = false
c <= d = true
c == d = false
c != d = true

Assignment Operators –

Operators	Expression	Translate to
+=	a = a + b	a.plusAssign(b) > 0
-=	a = a – b	a.minusAssign(b) < 0
*=	a = a * b	a.timesAssign(b)>= 0
/=	a = a / b	a.divAssign(b) <= 0
%=	a = a % b	a.remAssign(b)

Kotlin

fun main(args : Array<String>){
 var a = 10
    var b = 5
    a+=b
    println(a)
    a-=b
    println(a)
    a*=b
    println(a)
    a/=b
    println(a)
    a%=b
    println(a)

}

Output:

15
10
50
10
0

Unary Operators –

Operators	Expression	Translate to
++	++a or a++	a.inc()
—	–a or a–	a.dec()

Kotlin

fun main(args : Array<String>){
    var e=10
    var flag = true
    println("First print then increment: "+ e++)
    println("First increment then print: "+ ++e)
    println("First print then decrement: "+ e--)
    println("First decrement then print: "+ --e)
}

Output:

First print then increment: 10
First increment then print: 12
First print then decrement: 12
First decrement then print: 10

Logical Operators –

Operators	Meaning	Expression
&&	return true if all expressions are true	(a>b) && (a>c)
||	return true if any of expression is true	(a>b) || (a>c)
!	return complement of the expression	a.not()

Kotlin

fun main(args : Array<String>){
    var x = 100
    var y = 25
    var z = 10
    var result = false
    if(x > y && x > z)
     println(x)
    if(x < y || x > z)
     println(y)
    if( result.not())
     println("Logical operators")
}

Output: 

100
25
Logical operators

Bitwise Operators –

Operators	Meaning	Expression
shl	signed shift left	a.shl(b)
shr	signed shift right	a.shr(b)
ushr	unsigned shift right	a.ushr()
and	bitwise and	a.and(b)
or	bitwise or	a.or()
xor	bitwise xor	a.xor()
inv	bitwise inverse	a.inv()

Kotlin

fun main(args: Array<String>)
{
    println("5 signed shift left by 1 bit: " + 5.shl(1))
    println("10 signed shift right by 2 bits: : " + 10.shr(2))
    println("12 unsigned shift right by 2 bits:  " + 12.ushr(2))
    println("36 bitwise and 22: " + 36.and(22))
    println("36 bitwise or 22: " + 36.or(22))
    println("36 bitwise xor 22: " + 36.xor(22))
    println("14 bitwise inverse is: " + 14.inv())
}

Output:

5 signed shift left by 1 bit: 10
10 signed shift right by 2 bits: : 2
12 unsigned shift right by 2 bits:  3
36 bitwise and 22: 4
36 bitwise or 22: 54
36 bitwise xor 22: 50
14 bitwise inverse is: -15