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~                          Basically BASIC.                          ~
~                        Jonathan Rutherford.                        ~
~                                                                    ~
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Enough of the quiz program for  now.  I think everyone understands the
BASICS (no pun intended) of  it.  [Why's  it  in capitals then - Neil]
Lets take a look at strings now.

A lot of people seem to be  having  a bit trouble with strings. Not so
much the input or output of strings; more the manipulation [big word!]
of them.

Firstly, what is a string?

Strings are variables that use the Dollar ($) sign at the end of them.
Eg. A B C and would be variables that can hold numbers, but we added a
$ sign at the end of them to  make  them A$, B$ and C$ they would also
be able to hold alphabetical information.
We could ask a person to input a number using this short program:-

        Print "Please enter a number"
        Input A

This could then be converted to ask for a letter.

        Print "Please input a letter"
        Input A$

Strings can be more than 1  letter  long,  fro example we could have a
string represting someone's name as NAME$ and ask this question

        Print "Please enter your name"
        Input NAME$
        Print "Hello";NAME$

The good thing about using words for strings, are that they are easily
understood. Eg. The contents of a  string  called A$, would be hard to
guess, but a string marked COUNTRY$ would almost definately be holding
the name of a country.

There are a number of commands concerning the manipulation of strings,
but the commands that I tend  to  use  the  most are Upper$, Left$ and
STR$.

Upper$ is useful as it converts  any  lower case characters into upper
case characters. It is useful when comparing strings. Eg. You want the
computer to ask for a word and if the word is "DOG"it will print "woof
woof". As the computer  is  case  specific,  if  you  entered "dog" it
wouldn't recognise it. However  if  the  computer converted "dog" into
"DOG" it would print "Woof Woof" Here how to use the command UPPER$.

        Print "Enter a word"
        Input DOG$
        DOG$=Upper$(DOG$)
        If DOG$="DOG" then print "Woof Woof"

You put the name of the string  that  you  want to hold the upper case
information, followed by an equal (=)  sign; then the command "UPPER$"
then open the  brackets,  put  the  name  of  the  string  holding the
information inside the brackets and finally close the brackets.

eg. The word "heLlO" is held  inside  a string called "WORD$". We want
to put the word "HELLO"  (all  in  upper  case) inside a string called
"UPPERWORD$". We would type:-

        UPPERWORD$ = Upper$ (WORD$)

Left$ takes the  leftmost  character  of  a  string  and  puts  it ina
different string. Eg. If you wanted to  ask someone to give you a word
and you would tell them the first letter of that word.

        Print "Give me a word"
        Input Word$
        Letter$=Left$(Word$,1)
        Print "The first letter was";Letter$

The number inside the brackets  after  word$  is the number of letterS
from the left you want to include.
You could use left$ to make a simple typewriter effect:-

        For X=1 to 5
        Print Left$(Hello,X)
        Wait 5
        Next X


So to use Left$ you must put the command

        Left$ ( Sourcestring , Number of letters )

eg.     Print Left$ (A$,5)

Would print the 5th letter from  the  left  that was inside the string
called A$.

The other really useful string command I use is STR$. This is used for
converting a number held in a variable like  A or B, into a string. A$
or B$.

As you can't add strings together numerically, ie.

        A$="4" : B$="5": Add A$,B$

You could add to variables together, then combine them into a string.

        A=4: B=5: C= A+B : Answer$=Str$(C)

Hope you find the tips useful.

Jonathan