Furthermore, a character string is a group of characters which is enclosed in quotation
marks  such  as  "123".  This  is  not  a  numerical  value.  In  other  words,  "123"  just  happens
to  be  1  and  2  and  3  in  sequence  and  is  considered  the  same  as  "ABC".  A  character
variable  is  made  by  attaching  a  "$"  to  a  regular  variable  (A,  B,  X,  Y,  etc.).  These  can  be
freely  selected  from  within  this  range.
Example:  A$.B$,C$,X$,Y$
Comparison  or  addition  of  each  character  variable  is  possible  but  other  operations
such  as  subtraction,  multiplication  and  division  cannot  be  performed.
Example:  If  A$  =  "123"  and  B$  =  "456"
As  a  result  of  C$  =  A$  +  B$.  C$  becomes  "123456".
(For  C$  =  B$  +  A$,  C$  becomes  "456123".)
A  character  variable  can  contain  up  to  7  characters.
Also,  in  addition  to  these  character  variables,  there  is  also  an  exclusive  character
variable.
This  exclusive  character  variable  is  "$"  and  can  contain  up  to  30  characters.
E x a m p l e :  $ =  M  2 3 4 5 6 7 8 9 0 A B C D E  F G '
Since  this  exclusive  character  variable  can  use  a  character  function  (MID  function)
which will be explained later, it is much more convenient than other character variables.
•  Num erical  varia bles  a nd  cha racter  varia bles  w hich  c ontain  the  same  lette r  cann ot  be
used  at  the  same  time.
Numerical  variable  A—i
...  .  -Cannot  be  used  at  the  same  time.
Cha rac ter  va ria ble  A$- J
Since  numerical  variables  and  character  variables  use  the  same  memory,  they  cannot
be  used  at  the  same  time.
5-2-2  Substitution  Statements
BASIC  substitution  statements  are  in  the  following  format.
Variable  =  numerical  expression
In  a  BASIC  substitution  statement,  the  right  side  which  contains  addition,  subtraction,
multiplication  or  division  is  called  a  "numerical  expression".
Example:  y=2*X-F3
The  "25|cX+3"  on  the  right  side  is  a  numerical  expression.
The  does  not  mean  "equal",  it  means  "substitute".
In V= 2'l'X+3, the left side is the variable and the right side is the numerical expression.
In  other  words,  the  meaning  is  different  from  normal  mathematics  where  "the  left  side
(V)  and  the  right  side  (2*X+3)  are  equal".
It  means  "input  the  operation  result  of  the  right  side  (2*X+3)  into  the  left  side  (V)".
It  may  be  easier  to  understand  by  thinking  of  V  =  2  *X+3  as  Y  ■<-  25)«X+3.
-29-