Things you find inside a computer program/algorithm
- Consider the
Euclid's Algorithm that we
have learned:
As long as neither number is equal to zero (0) do
{
if ( A > B )
replace A with the value (A - B)
otherwise
replace B with the value (B - A)
}
if ( A > 0 )
The Greatest Common Divisor is A
otherwise
The Greatest Common Divisor is B
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|
You can see that
the
algorithm contains
2 kinds
of "things"...
Things you find inside a computer program/algorithm
- (1)
The computer algorithm/program contains
instructions
a.k.a.
statements:
As long as neither number is equal to zero (0) do
{
if ( A > B )
replace A with the value (A - B)
otherwise
replace B with the value (B - A)
}
if ( A > 0 )
The Greatest Common Divisor is A
otherwise
The Greatest Common Divisor is B
|
|
Statements tell
the computer
what
operation it
needs to
perform/execute
Things you find inside a computer program/algorithm
- (2)
The computer algorithm/program contains
(memory) variables:
As long as neither number is equal to zero (0) do
{
if ( A > B )
replace A with the value (A - B)
otherwise
replace B with the value (B - A)
}
if ( A > 0 )
The Greatest Common Divisor is A
otherwise
The Greatest Common Divisor is B
|
|
Variables
store
the necessary
information
used by the statements of
the
computer algorithm
Program organization (packaging)
- Statements and
variables are
organized into
coherent units
to help programmers
manage their program code:
- Statements and
variables that
are used to
perform an
important task is
grouped together into
one
program unit
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- The
program unit
used to
package/contain
statements and
variables that
perform an
important task is called
by different names:
-
Method (in Java)
-
Function (in C and
Python)
or
- Procedure
- Subroutine
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|
Some
programming language
can
group
multiple
(related)
functions into
larger units --- like a
class in
Java
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