The general format of the while statement is:

while (condition) {
  statement
}

Note that a while loop may never execute the statement. The statement is executed repeatedly until condition becomes false.

In contrast, a repeat loop has the general format as below:

repeat {
  print('test')
}

repeat statement will execute at least once, and continue until it is explicitly interrupted with a break statement. In fact, break will immediately exit from any loop structure.

Unlike for loop which iterates over a vector list, for using while loop you need to have an indicator variable i and change its value within each iteration. Otherwise you will have an infinite loop.

Example: While Loop

The following example shows how to calculate factorial of 10 using the while loop.