import scala.collection.mutable.ArrayBuffer

case class Task(id: Int, description: String, priority: String)

object TaskManager {
  private val tasks = ArrayBuffer[Task]()

  def addTask(description: String, priority: String): Unit = {
    val taskId = if (tasks.isEmpty) 1 else tasks.map(_.id).max + 1
    val newTask = Task(taskId, description, priority)
    tasks += newTask
    println(s"Task added: ${newTask.id} - ${newTask.description} [Priority: ${newTask.priority}]")
  }

  def viewTasks(): Unit = {
    if (tasks.isEmpty) {
      println("No tasks available.")
    } else {
      println("ID | Description                    | Priority")
      tasks.foreach { task =>
        println(f"${task.id}%2d | ${task.description}%30s | ${task.priority}%8s")
      }
    }
  }

  def deleteTask(id: Int): Unit = {
    tasks.indexWhere(_.id == id) match {
      case -1 => println(s"Task with ID $id not found.")
      case index =>
        val deletedTask = tasks.remove(index)
        println(s"Task deleted: ${deletedTask.id} - ${deletedTask.description}")
    }
  }
}

object TaskManagerApp {
  def main(args: Array[String]): Unit = {
    println("Welcome to Task Manager!")

    var running = true
    while (running) {
      println("\nSelect an option:")
      println("1. Add Task")
      println("2. View Tasks")
      println("3. Delete Task")
      println("4. Exit")
      print("Enter your choice: ")

      scala.io.StdIn.readInt() match {
        case 1 =>
          print("Enter task description: ")
          val description = scala.io.StdIn.readLine()
          print("Enter task priority: ")
          val priority = scala.io.StdIn.readLine()
          TaskManager.addTask(description, priority)
        case 2 =>
          println("\nTasks:")
          TaskManager.viewTasks()
        case 3 =>
          print("Enter ID of the task to delete: ")
          val taskId = scala.io.StdIn.readInt()
          TaskManager.deleteTask(taskId)
        case 4 =>
          println("Exiting Task Manager.")
          running = false
        case _ =>
          println("Invalid option. Please select a valid option.")
      }
    }
  }
}
by

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Read input from STDIN in Scala

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object Hello {
	def main(args: Array[String]): Unit = {
	  val name = scala.io.StdIn.readLine()        // Read input from STDIN
    println("Hello " + name ) 
	}
}

About Scala

Scala is both object-oriented and functional programming language by Martin Odersky in the year 2003.

Syntax help

Variables

Variable is a name given to the storage area in order to identify them in our programs.

var or val Variable-name [: Data-Type] = [Initial Value];

Loops and conditional statements

1. If family:

If, If-else, Nested-Ifs are used when you want to perform a certain set of operations based on conditional expressions.

If

if(conditional-expression){    
//code    
}

If-else

if(conditional-expression) {  
//code if condition is true  
} else {  
//code if condition is false  
}

Nested-If-else

if(condition-expression1) {  
//code if above condition is true  
} else if (condition-expression2) {  
//code if above condition is true  
}  
else if(condition-expression3) {  
//code if above condition is true  
}  
...  
else {  
//code if all the above conditions are false  
}

2. For:

For loop is used to iterate a set of statements based on a criteria.

for(index <- range){  
  // code  
}

3. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition) {  
 // code 
}

4. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {
  // code 
} while (condition)

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.

def functionname(parameters : parameters-type) : returntype = {   //code
}

Note:

You can either use = or not in the function definition. If = is not present, function will not return any value.