Kotlin when Expression
Kotlin, when expression is a conditional expression which returns the value. Kotlin, when expression is replacement of switch statement. Kotlin, when expression works as a switch statement of other language (Java, C++, C).
Using when as an Expression
Let's see a simple example of when expression.
fun main(args: Array
var number = 4
var numberProvided = when(number) {
1 -> "One"
2 -> "Two"
3 -> "Three"
4 -> "Four"
5 -> "Five"
else -> "invalid number"
}
println("You provide $numberProvided")
}
Output:
You provide Four
Using when Without Expression
It is not mandatory to use when as an expression, it can be used as normally as it used in other language.
For Example
fun main(args: Array
var number = 4
when(number) {
1 -> println("One")
2 -> println("Two")
3 -> println("Three")
4 -> println("Four")
5 -> println("Five")
else -> println("invalid number")
}
}
Output:
Four
Multiple Statement of when Using Braces
We can use multiple statement enclosed within block of condition.
For Example
fun main(args: Array
var number = 1
when(number) {
1 -> {
println("Monday")
println("First day of the week")
}
7 -> println("Sunday")
else -> println("Other days")
}
}
Output:
Monday
First day of the week
Multiple branches of when
We can use multiple branches of condition separated with a comma. It is used, when we need to run a same logic for multiple choices.
fun main(args: Array
var number = 8
when(number) {
3, 4, 5, 6 ->
println("It is summer season")
7, 8, 9 ->
println("It is rainy season")
10, 11 ->
println("It is autumn season")
12, 1, 2 ->
println("It is winter season")
else -> println("invalid input")
}
}
Output:
It is rainy season
Using when in the range
The when expression also check the ranges of input provided in when condition. A range is created using .. (double dot) operator. The in operator is used to check if a value belongs to a range.
For Example:
fun main(args: Array
var number = 7
when(number) {
in 1..5 -> println("Input is provided in the range 1 to 5")
in 6..10 -> println("Input is provided in the range 6 to 10")
else -> println("none of the above")
}
}
Output:
Input is provided in the range 6 to 10
I NTRODUCTION TO OOP,CLASSES & OBJECTS 1. Use of scope Resolution of Operators. 2. Define a function outside a using scope resolution operators. 3. Write a program to calculate the area of circle, rectangle and square using function overloading. 4. Write a program to calculate the area of circle, rectangle and square using with class & object. 5. Write a program to demonstrate the use of returning a reference variable. 6. Create a class student,stores the details about name,roll no,marks of 5 subject,1.get function accept value of data members,2. display function to display,3.total function to return total of 5 subjects marks. 7. Create function power() in c++. & Create function power() in c++ and default argument. 8. Write a C++ program to swap the value of private data members from 2 different classes. 9. Write a program to illustrate the use of this pointer. 10. An election is contested by five candidates. The candidates are numbered 1 to 5 and the voting is do...
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