Atari 400

Introduction to Atari BASIC 47
BASIC Variables
So far, we have only discussed data constants. A constant can be
defined as a fixed val ue. The following are examples of string and
numeric constants.
"Jack Novet"
"375"
27.59
o
100000
A name can be used to express data as well as a constant.
Variables are used to express data as a name.
A variable can be
defined as a quantity that can assume anyone
of a group of values. Variables are represented by variable
names. These consist
of a letter followed optionally by additional
letters and/ or numbers. The value assumed by a variable is
subject to change, depending upon the program statement
being executed . For example , in the following,
100 LET A = 5.0
200 LET B = 7.0
300 LET A = A + B
the variable A
is initially assigned a value of 5.0and B is assigned a
value
of 7.0. In line 300 , the variable A is assigned a new value
equal
to the sum of variables A and B, which is 12.0. The previous
value of A is erased.
Note the use of the LETsta tement in the preceding example . The
LET statement is used to assign a value to a variable. Whenever a
LET statement is used in a program, the value of the variable on
the left side of the equation is to be replaced with the value
appearing
on the right.
The reserved
word , LET need not actually be included in a LET
statement. Both of the following statements have the same