puppybasic intro ch. 05 - strings part i

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strings part i:  the indispensable                                       
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                  an intro to puppybasic                                 
                                                                         
                  chapter 5: strings part i                              
                                                                         
                                                                         
                                                                         
                                                                         
                                                                         
                                                                         
                                                                         
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strings part i:  the indispensable                                       
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although you need to talk to the computer to write a program, and you    
usually need math to talk to the computer, you usually need strings      
(which may contain plain english) to talk to the person using the        
computer. for this and other reasons, strings are generally as vital to  
your program as numbers. here are some statements to work with strings:  
                                                                         
UCASE$                                                                   
                                                                         
q$=UCASE$(q$) will convert q$ to an all uppercase copy of itself. the    
lowercase version is:                                                    
                                                                         
                                                                         
                                                                         
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strings part i:  the indispensable                                       
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LCASE$                                                                   
                                                                         
q$=LCASE$(q$) when you've printed "press q to quit" can be the           
difference between a person being able to exit your program when they    
want to and being able to a bit later (when someone points out that      
their caps lock light is on.) it is possible to turn off someone's caps  
lock for them using program code, but processing strings with LCASE$ is  
easier and more considerate.                                             
                                       _________________________________ 
q$="NAME@PUPPY.Com": PRINT LCASE$(q$)  _name@puppy.com__________________ 
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strings part i:  the indispensable                                       
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CHR$ is indispensable: there are 256 different ASCII characters, (for    
example, the lowercase letter "a" is ASCII 97, and a space, like from    
the spacebar, is ASCII 32.) including letters, numbers, punctuation, and 
other fun symbols (ASCII 01 is a smiley face. ☺ for the most part, the   
only way to produce some of them is with CHR$. for instance, if you want 
to produce a double quote on the screen, or within a string, you can use 
the following code: (put it all on the same line, of course...)          
? "i have been learning about puppybasic from "+CHR$(34)+"an intro to 
puppybasic"+CHR$(34)+" and it's okay..."                  
                                                                         
...as ASCII 34 is the same double quote you would get from the keyboard. 
                                                                         
                                                                         
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strings part i:  the indispensable                                       
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+------+---------------------------------------------------------------+ 
| CHR$ | also lets you "print" shadows and lines using text symbols... | 
+------+---------------------------------------------------------------+ 
the reverse of CHR$, the ASC function, gives you the code number for the 
first byte of a string:                                                  
                                                                         
? ASC("a") -3  _________________________________________________________ 
will print:    __94_____________________________________________________ 
               _________________________________________________________ 
                                                                         
as ascii 97, in puppybasic coded as: CHR$(97) is "a", and 97 -3 is 94.       
                                                                         
                                                                         
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strings part i:  the indispensable                                       
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LEN... n = LEN(q$) will set n to a number equal to the number of bytes   
in a string - examples: LEN("hello") is equal to 5, LEN("how are you?")  
is equal to twelve. spaces and punctuation count.                        
                                                                         
lastly, as you can convert a string to a number using VAL, you can       
convert a number to a string using STR$ so:                              
                                                                         
sp = 5                                                                   
q$ = "you pressed spacebar" + STR$(sp-1) + "times."                      
                                                                         
will store the string: "you pressed spacebar 4 times." in q$.            
                                                                         
                                                                         
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strings part i:  the indispensable                                       
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you are well on your way to learning puppybasic! the best thing you can 
do with this tutorial is read it slowly, think about each page and what  
kind of program you could write with each command, and experiment with   
the code in puppybasic (type it in, you learn faster that way, even 
though you *could* cut and paste...) for a feel of what coding is really 
like.  
                                                                         
and never forget to have fun.                                            
                                                                         
                         -= end of chapter 5 =-                          
                                                                         
                                                                         
                                                                         
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an intro to puppybasic                                       (chapter 5) 
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