83Plus:Basic:Tricks - Revision history

Zeda: Pause affects the Ans variable, another case when Pause after Disp is valid.

2018-09-13T22:47:36Z

Pause affects the Ans variable, another case when Pause after Disp is valid.

123outerme: Combined "never write closing parentheses or quotes"

2014-10-19T18:27:06Z

Combined "never write closing parentheses or quotes"

Sircmpwn: added section on avoiding memory leaks

2011-08-08T19:19:43Z

added section on avoiding memory leaks

Bfr: Forgot a "Then"

2009-01-02T19:34:19Z

Forgot a "Then"

Bfr: Formatting

2009-01-02T19:33:13Z

Formatting

Bfr at 19:30, 2 January 2009

2009-01-02T19:30:41Z

Bfr: Another way to detect radian/degree mode

2009-01-02T19:22:55Z

Another way to detect radian/degree mode

Saibot84: more memory efficient numerical sub( function

2007-04-10T19:32:53Z

more memory efficient numerical sub( function

Saibot84: added routines category

2007-04-10T19:26:16Z

added routines category

Burr: Fixed the list

2006-12-13T07:53:57Z

Fixed the list

@@ Line 16: / Line 16: @@
 ===Memory Saving===<!-- â†’â‰ â‰¤â‰¥ -->
 ;Never write out closing ''')''' or '''"''' (parentheses/quotes) at the end of a line:You save '''1''' byte. The reason for this is that TIOS closes all still-open parentheses when it encounters $3F, which is the new-line character that is input when you press enter in the Program Editor, or when it encounters the store arrow.
-;Never use a Pause right after a Disp, unless the Pause has text:This is because both Disp and Pause can display text to the homescreen. Disp writes the text to the screen and then continues forward, but Pause waits for the [ENTER] key to be pressed.  When Pause is used with text, such as in
+;Never use a Pause right after a Disp, unless the Pause has text or you need to preserve Ans:This is because both Disp and Pause can display text to the homescreen. Disp writes the text to the screen and then continues forward, but Pause waits for the [ENTER] key to be pressed.  When Pause is used with text, such as in
   :Pause "TEXT"
 :then it writes the text to the homescreen first, and then waits for the user to press [ENTER].
@@ Line 34: / Line 34: @@
   Archive XArchive YArchive ZUnarchive ZUnarchive TDelVar ADelVar BFor(X,0,1
 :this doesn't work with Lists, or labels, and presumably neither with the prgm token.
 ===Avoiding Memory Leaks===
 Memory leaks can pose a serious problem to TI-Basic developers writing more advanced programs.  Specifically, TI-Basic doesn't allow you to effectively Goto out of a loop.  Take the following code:

@@ Line 15: / Line 15: @@
 ===Memory Saving===<!-- â†’â‰ â‰¤â‰¥ -->
-;Never write out closing ''')''' parentheses at the end of a line:You save '''1''' byte. The reason for this is that TIOS closes all still-open parentheses when it encounters $3F, which is the new-line character that is input when you press enter in the Program Editor, or when it encounters the store arrow.
+;Never write out closing ''')''' or '''"''' (parentheses/quotes) at the end of a line:You save '''1''' byte. The reason for this is that TIOS closes all still-open parentheses when it encounters $3F, which is the new-line character that is input when you press enter in the Program Editor, or when it encounters the store arrow.
-;Never write out closing '''"''' quotes at the end of a line: You save '''1''' byte. The reason for this is that TIOS closes any still-open quotes when it encounters $3F, which is the new-line character that is input when you press enter in the Program Editor, or when it encounters the store arrow.
 ;Never use a Pause right after a Disp, unless the Pause has text:This is because both Disp and Pause can display text to the homescreen. Disp writes the text to the screen and then continues forward, but Pause waits for the [ENTER] key to be pressed.  When Pause is used with text, such as in
   :Pause "TEXT"

@@ Line 35: / Line 35: @@
   Archive XArchive YArchive ZUnarchive ZUnarchive TDelVar ADelVar BFor(X,0,1
 :this doesn't work with Lists, or labels, and presumably neither with the prgm token.
 ==Speed Boosters==<!-- â†’â‰ â‰¤â‰¥ -->

@@ Line 155: / Line 155: @@
 Similarly, you can also use sin(&pi;), which only returns 0 if in radian mode, to do something like
   <nowiki>:If sin(&pi;
 :Disp "Degree Mode
 :Else

@@ Line 154: / Line 154: @@
 :End</nowiki>
 Similarly, you can also use sin(&pi;), which only returns 0 if in radian mode, to do something like
-<nowiki>:If sin(&pi;
+ <nowiki>:If sin(&pi;
 :Disp "Degree Mode
 :Else

@@ Line 153: / Line 153: @@
 :Disp "Radian Mode
 :End</nowiki>
 ;Ans as a list:It is possible to use the Ans variable as a list in replacement to using any of the real or complex variables.  The trick is knowing how to use the augment( and the seq( commands so that you won't be destroying Ans and inadvertedly converting it into something other than a list. '''NOTE: '''extensive usage of this, as in the case of replacing all variables from a program can/will slow down the program, as well as use up more memory than if you just used variables. A shellsort program using variables A,B,C,D,L,Z, and &theta; used up 143 bytes, while its variable-free counterpart used up 645 bytes and was significantly slower. However, this doesn't mean the technique is completely useless.
 :*augment({1,2},{3,4}  will return {1,2,3,4}... it can only augment 2 lists at a time, so repeated usage will be necessary to maintain the Ans variable as a list

@@ Line 9: / Line 9: @@
 ===Memory Management===<!-- â†’â‰ â‰¤â‰¥  -->
 ;Number values:In order to be able to save memory on the calculator, it helps to have a bit of an understanding as to how the calc manages the memory, especially in regards to numbers. Because TIOS is designed for school, and so is oriented for precision, it saves all real number values as 14-digits and an exponent of 10. In other words, it saves the number &pi; as 3.1415926535898 &times; 10<sup>0</sup>, but in memory, it is something more similar (not exact) to <code>0 31415926535898</code> where the 0 tells TIOS what the exponent of 10 is that need to be applied to the 31415926535898.  However, this also applies to smaller values, such that a 13 is saved as <code>1 13000000000000</code>.  For small, rational, terminating values, it can be seen that a good deal of memory is being wasted.  I've created the following formula which, when saved to Y0 (or any other Y function, works with numbers in the same way that the sub( function works with strings:
-  int(fPart(X/10^(int(2-A+log(X))))*10^(F))
+  int(10^(F)fPart(X/10^(int(2-A+log(X
 :translated as a sub( statement, it would be the equivalent of sub(X,A,F) regardless of the position of the decimal point in X.  If you don't understand what the formula is doing, it's dividing X by 10<sup>value</sup> so that the digit we're looking for (identified in A) is "moved" to be the first digit to the right of the decimal point, then ignores anything to the left or the decimal piont, then multiplies the value left over by 10<sup>F</sup> and ignores anything to the right of the decimal point, thus providing the sub(X,A,F).
 ;use more than 27 vars:If you need to use more than the 27 vars TIOS gives you with A-Z, other than using lists, matrices, strings, or Ans, you can go look in the [VARS] menu under Window.  Of these, being that the calculator is usually in function mode, you can use any of the window vars under T/theta (which are for parametric mode) and/or under U/V/W (which are for polar).  It is recommended that you prefer those under U/V/W because this mode is usually never used, whereas parametric has been used on more than one occasion by programs, such as for drawing X in terms of Y. You can also go into the Finance menu under [APPS] and go to Vars, but IIRC, some are read-only vars, so you will need to experiment to see if a var is accessible or not, but it is certain, that at least the '''N''' can be used problemlessly in your programs. You can also use the ''n'', which is found by going to the catalog and pressing "N" as a variable, as well as the sequential functions u,v, and w.

← Older revision		Revision as of 19:26, 10 April 2007
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	[[Category:83Plus:Basic\|Tricks]]		[[Category:83Plus:Basic\|Tricks]]
		+	[[Category:83Plus:Basic:Routines\|Tricks]]

	There is a whole list of tricks that one can implement, once one is comfortable programming in TI-Basic which allow for a whole onslaught of capabilities, such as using less memory or making the program run faster. There used to be a site called Kevtiva Inc. which had the largest list of TI-BASIC hacks I (Saibot84) have ever seen, including how to force a RAM reset (without the use of asm programs) but I've forgotten most of the meanest hacks. Here are some of the many tricks: (Please use common sense in deciding whether a "-" is a minus or a negative sign. When the use is un-common-sense-ical or possibly confusing, it will be specified.)		There is a whole list of tricks that one can implement, once one is comfortable programming in TI-Basic which allow for a whole onslaught of capabilities, such as using less memory or making the program run faster. There used to be a site called Kevtiva Inc. which had the largest list of TI-BASIC hacks I (Saibot84) have ever seen, including how to force a RAM reset (without the use of asm programs) but I've forgotten most of the meanest hacks. Here are some of the many tricks: (Please use common sense in deciding whether a "-" is a minus or a negative sign. When the use is un-common-sense-ical or possibly confusing, it will be specified.)

@@ Line 184: / Line 184: @@
 ==Further Reading==<!-- â†’â‰ â‰¤â‰¥ -->
 '''The Complete TI-83 BASIC Optimization Guide, Version 2''' [http://www.ticalc.org/archives/files/fileinfo/145/14542.html]
 '''TI-Basic Developer'''
 [http://tibasicdev.wikidot.com]