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While Loops

Remarks:

The primary difference between while and do-while loops is whether they execute the block_expression before they check to see if they should loop.

Because while and do-while loops rely on an expression to evaluate to false to terminate, they often require mutable state to be declared outside the loop and then modified inside the loop.

While Loops

var line = 0
var maximum_lines = 5

while (line < maximum_lines) {
  line = line + 1
  println("Line number: " + line)
}

Do-While Loops

var line = 0
var maximum_lines = 5

do {
  line = line + 1
  println("Line number: " + line)
} while (line < maximum_lines)

The do/while loop is infrequently used in functional programming, but can be used to work around the lack of support for the break/continue construct, as seen in other languages:

if(initial_condition) do if(filter) {
  ...
} while(continuation_condition)

Syntax:

while (boolean_expression) { block_expression }
do { block_expression } while (boolean_expression)

Parameters:

Parameter	Details
`boolean_expression`	Any expression that will evaluate to `true` or `false`.
`block_expression`	Any expression or set of expressions that will be evaluated if the `boolean_expression` evaluates to `true`.

Contributors

Topic Id: 650

Example Ids: 2128,2129

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