83Plus:Basic:While - Revision history

130.215.239.90: unicoded

2005-12-10T00:49:20Z

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2005-12-09T23:11:20Z

Removed preceding semicolons

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2005-12-09T22:25:16Z

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70.150.174.3: /* Comments */

2005-12-05T16:55:21Z

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70.150.174.3 at 16:53, 5 December 2005

2005-12-05T16:53:43Z

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[[Category:83Plus:Basic:Conditionals|While]]
== Synopsis ==
'''Token Size:''' 1 byte

'''Syntax:'''
:While ''condition''
:''command''
:End

The while command is used to execute a command or series of commands when a variable shares a given relationship with another variable or a value. A ''While'' command will continue to execute everything before the next ''End'' until the given condition is no longer met.

== Comments ==
Use of a Goto statement within an While statement will cause an increase in memory allocation, leading to program slowdowns and eventually a MEMORY error. For example, the following code will eventually cause an error:

<nowiki>0->X ;-> == STO operator
Lbl 0
While X=1
X+1->X
Disp X
Goto 0
End</nowiki>

If you must use a Goto within an While statement, it is possible to trick the 83+ into thinking the block ended by jumping to an otherwise unused label that uses an End statement followed by a jump to the proper label. For example, the above program could be rewritten like so:

<nowiki>0->X
Lbl 0
While X=1
X+1->X
Disp X
Goto 2
End
Return

Lbl 2
End
Goto 0</nowiki>

This would avoid the problem by causing the 83+ to terminate the While conditional prior to jumping.

== Examples ==
<nowiki>
:While X =/= 105
:Getkey -> G
:End
</nowiki>
Or, if you desire the use of other operators, such as And, Or, or Xor:
<nowiki>
:While X=5 and Y=/=3
:Input "",A
:A+X->Y
:End
</nowiki>

@@ Line 16: / Line 16: @@
 Lbl 0
 While X=1
-X+1->X
+X+1â†’X
 Disp X
 Goto 0
@@ Line 23: / Line 23: @@
 If you must use a Goto within an While statement, it is possible to trick the 83+ into thinking the block ended by jumping to an otherwise unused label that uses an End statement followed by a jump to the proper label. For example, the above program could be rewritten like so:
-  <nowiki>0->X
+  <nowiki>0â†’X
 Lbl 0
 While X=1
-X+1->X
+X+1â†’X
 Disp X
 Goto 2
@@ Line 40: / Line 40: @@
 == Examples ==
   <nowiki>
-While X =/= 105
+While Gâ‰ 105
-Getkey -> G
+getKeyâ†’G
 End</nowiki>
 Or, if you desire the use of other operators, such as And, Or, or Xor:
   <nowiki>
-While X=5 and Y=/=3
+While X=5 and Yâ‰ 3
 Input "",A
-A+X->Y
+A+Xâ†’Y
 End</nowiki>

@@ Line 13: / Line 13: @@
 Use of a Goto statement within an While statement will cause an increase in memory allocation, leading to program slowdowns and eventually a MEMORY error. For example, the following code will eventually cause an error:
-  <nowiki>0->X ;-> == STO operator
+  <nowiki>
 Lbl 0
 While X=1
@@ Line 37: / Line 37: @@
 This would avoid the problem by causing the 83+ to terminate the While conditional prior to jumping.
 == Examples ==