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The while loop in Scala

The while loop is used to run a block of code multiple time until a specific condition is true. In this tutorial, we will learn about while loop its use, syntax, example.
Submitted by Shivang Yadav, on June 23, 2019

while loop in Scala

while loop in Scala is used to run a block of code multiple numbers of time. The number of executions is defined by an entry condition. If this condition is TRUE the code will run otherwise it will not run.

while loop is used when the program does not have information about the exact number of executions taking place. The number of executions is defined by an entry condition that can be any variable or expression, the value evaluated in TRUE if it's positive and FALSE if it's zero.

This loop might not run even once in the life span of code. If the condition is initially FALSE. The flow will not go in to loop in this case.

The while loop is also called entry controlled loop because its condition is checked before the execution of the loop's code block.

Syntax of while loop:

    while(condition){
	    //Code to be executed...
    } 

Flow chart of while loop:

Example of while loop:

object MyClass {
      def main(args: Array[String]) {
          var myVar = 2; 
          println("This code prints 2's table upto 10")
          while(myVar <= 10){
              println(myVar)
              myVar += 2;
          }
      }
   }

Output

This code prints 2's table upto 10
2
4
6
8
10

Code explanation:

The above code is to explain the usage of while loop in Scala. In this code, we have used a variable named myVar that is used as a counter in while loop. For printing text, to the screen, we are using println method that moves the cursor to the next line after printing. We have used += assignment operator that we have learned previously. The code prints that table of 2 up to 10.

From this section, I am going to give you assignments that you can complete and submit to know your progress.

Assignment 1 (difficulty - beginner): Print all numbers from 100 - 399 that are divisible by 3. (use while loop and functions.)

Assignment 2 (difficulty - intermediate): Print all number between 541 - 643 that have 3, 5 and 7 as a factor.