Kotlin If Else Statements

This if-else is a keyword that are used to define conditional statement. This statement is based on an expression or boolean values. expression result is always should be in form of boolean value. This boolean value is true then executes if-block statement. Otherwise check other else-if statements or executes else-block statement. This else statement is optionally, when if-block condition are not satisfied.

if(expression){
  //true expression
}else{
  //false expression
}

For example

fun main(args: Array<String>) {
    var number:Int =5
    if(number==5){
        print("number is Five")
    }else{
        print("number is not Five")
    }
}

Output

number is Five

We can also make ternary operators using of if-else statements.

fun main(args: Array<String>) {
 
   val num1:Int =10
   val num2:Int =20
   //implement ternary operator
   val big:Int  =if(num1>num2) num1 else num2
   println("$big")
}

Output

20

Kotlin if.. else if.. else

when checking multiple condition into single or multiple variable then we can use if and else-if statement.

if(expresion1){
  //logical code
}else if(expression2){
  //logical code
  //group of statements
}else if(expression3){
  //logical code
  //group of statements
}else{
   //else portion
}

for example.

fun main(args: Array<String>) {
 
   var grade:Char='A'
   
   if(grade=='A'){
      //when grade value is equal to A
      println("Pass, with excellent marks")
   }else if(grade=='B'){
      println("Pass, with Good marks")
   }
   else if(grade=='C'){
      println("Pass, with Average marks")
   }else{
      //executes this block when not 
      //satisfied above all condition
      println("Result is Pending")
   }
}

Output

Pass, with excellent marks

Kotlin Nested If else Statement

Defining of one statement inside other statement that is called nested statement. some of situation we can need to define the nested statement in our program.

if(expression){
   //statements
   if(inner-expression2){
      //statements
      if(sub-expression1){
         //statements
      }else if(sub-expression2){
         //statements
      }
   }
   if(inner-expression2){
      //statements
   }
}

For example.

fun main(args: Array<String>) {
 
   var num:Int=100

   if(num<1000){
      //nested statement
      if(num<500){
         println("Num is less than to 500")
      }else{
         println("Num is greater than or equal to 500")
      }
   }else{
      println("Num is greater than or equal to 1000")
   }
}

Output

Num is less than to 500