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A variable is a named storage location that can be set to a particular value which can be used in subsequent computations. For example, we store a value of 5 in the variable
a
with the statement
a=5
. This value remains in
a
until we store a different value (for example, using the command
a=100
) or we clear
a
using the command
clear a
. Once a variable is set to a particular value, we can get this value by using the variable name in an expression (e.g.
a/2
).
Suppose we wish to compute the circumference of a circle of diameter 5 units using the formula
$c=d$ . We could first set the variable
d
to a value of 5:
>>d = 5
d =5.000
Then we could compute the circumference and assign its value to the variable
c
:
>>c = pi*d
c =15.708
In this command, the product of the value of
d
(which is known because we earlier set it to 5) and the value of
pi
(which is a pre defined variable) is computed and the value of the product is stored in the variable
c
.
Variable names must begin with an upper or lowercase letter. They may contain letters, digits, and underscores; they may not contain spaces or punctuation characters. Variable names are case sensitive, so
A
and
a
are different variables.
Which of the following are valid variable names?
a
B
ecky_ecky_ecky_ecky_ptang_zoo_boing
ecky ecky ecky ecky ptang zoo boing
2nd
JohnBigboote
There are several predefined variables. The most commonly used include
ans
 the default variable in which computation results are stored.pi
.i
or
j

$\sqrt{1}$ .clear
command.
Variables can contain several types of numerical values. These types include the following:
c
and
d
in
are scalar variables.Notification Switch
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