Other Looping Constructs

The other useful Smojo looping constructs are

BEGIN

UNTIL

and

AGAIN

Example 1

This loop will never terminate

	
	: never-ending
		begin "hi" . cr again ;

Example 2

Use

UNTIL

if you need to check for a condition to terminate

	
	: 5count
		0 begin 1+ dup . dup 5 > until ; 
	
	5count
	1 2 3 4 5 6 ok

Example 3

You can also use

WHILE-REPEAT

loops

	
	: 4chan
		0 begin 
			1+ 
			dup 5 < while "Ho!" . 
		repeat
	; 
	
	4chan
	Ho! Ho! Ho! Ho! ok

Quiz

Rewrite

4CHAN

using

BEGIN

AGAIN

and

EXIT

		: 4chan
			0 begin 
				1+ 
				dup 5 = if exit then
				"Ho!" . 
			again
		; 

		4chan

Write a word

SQUARES

which prints all the square numbers which are less then 1000 using the looping constructs above.

		: squares
			0 begin
				1+
				dup 2 ^ 
				dup 1000 < while .
			repeat
		;
	
		squares

Write a word

TRIANGLE9

which prints the following.

	1 
	2 2 
	3 3 3 
	4 4 4 4 
	5 5 5 5 5 
	6 6 6 6 6 6 
	7 7 7 7 7 7 7 
	8 8 8 8 8 8 8 8 
	9 9 9 9 9 9 9 9 9

		: triangle9
			0 begin
				1+
				dup 0 do
					dup .
				loop
				cr
			dup 9 = until
		;
	
		triangle9

Next: Local Words