This topic is about Scala Collections – Stack.
Stack is Last In First Out, LIFO data structure and allows to insert and retrieve element at top, in LIFO manner.
Declaring Stack Variables
The following is the syntax for declaring an Stack variable.
Syntax
val stack = Stack(1, 2, 3, 4, 5)
Here, stack is declared as an Stack of numbers. Value can be added at top by using commands like the following −
Command
stack.push(6)
Value can be retrived from top by using commands like the following −
Command
stack.top
Value can be removed from top by using commands like the following −
Command
stack.pop
Processing Stack
Below is an example program of showing how to create, initialize and process Stack −
Example
import scala.collection.mutable.Stack
object Demo {
def main(args: Array[String]) = {
var stack: Stack[Int] = Stack();
// Add elements
stack.push(1);
stack.push(2);
// Print element at top
println("Top Element: " + stack.top)
// Print element
println("Removed Element: " + stack.pop())
// Print element
println("Top Element: " + stack.top)
}
}
Save the above program in Demo.scala. The following commands are used to compile and execute this program.
Command
\>scalac Demo.scala \>scala Demo
Output
Top Element: 2 Removed Element: 2 Top Element: 1
In this chapter we learned about Scala Collections – Stack. To know more, Clikc Here.