Scala Loop Types

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There may be a situation, when you need to execute a block of code several number of times. In general, statements are executed sequentially: The first statement in a function is executed first, followed by the second, and so on.

Programming languages provide various control structures that allow for more complicated execution paths.

A loop statement allows us to execute a statement or group of statements multiple times and following is the general from of a loop statement in most of the programming languages:

Loop Architecture

Scala programming language provides the following types of loops to handle looping requirements. Click the following links to check their detail.

Loop TypeDescription
while loopRepeats a statement or group of statements while a given condition is true. It tests the condition before executing the loop body.
do...while loopLike a while statement, except that it tests the condition at the end of the loop body
for loopExecutes a sequence of statements multiple times and abbreviates the code that manages the loop variable.

Loop Control Statements:

Loop control statements change execution from its normal sequence. When execution leaves a scope, all automatic objects that were created in that scope are destroyed. As such Scala does not support break or continue statement like Java does but starting from Scala version 2.8, there is a way to break the loops. Click the following links to check the detail.

Control StatementDescription
break statementTerminates the loop statement and transfers execution to the statement immediately following the loop.

The Infinite Loop:

A loop becomes infinite loop if a condition never becomes false. If you are using Scala, the while loop is the best way to implement infinite loop as follows

object Test {
   def main(args: Array[String]) {
      var a = 10;
      // An infinite loop.
      while( true ){
         println( "Value of a: " + a );
      }
   }
}

If you will execute above code, it will go in infinite loop whcih you can terminate by pressing Ctrl + C keys.



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