Things you find inside a computer program/algorithm
- Consider the
Euclid's Algorithm that we
have learned:
Repeat until (A == 0 or B == 0):
{
if ( A > B )
replace A with the value (A - B)
otherwise
replace B with the value (B - A)
}
if ( A is not equal to 0 )
The Greatest Common Divisor = A
otherwise
The Greatest Common Divisor = B
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You can see that
the
algorithm contains
2 types of things !!
Things you find inside a computer program/algorithm
- (1)
The computer algorithm/program contains
commands
a.k.a.
statements:
Repeat until (A == 0 or B == 0): <--- Repetition statement
{
if ( A > B ) <--- Conditional statement
replace A with the value (A - B) <--- Assignment statement
otherwise
replace B with the value (B - A)
}
if ( A is not equal to 0 )
The Greatest Common Divisor = A
otherwise
The Greatest Common Divisor = B
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Commands or "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
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Variables store
the necessary
information
used by the statements of
the
computer algorithm
Program organization (packaging)
- Statements and
variables are
organized in
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 unit
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- The program unit used to
package/contain
statements and
variables that
perform an
important task is called:
-
Function (in Python and
C)
or
-
Method (in Java)
- Procedure
- Subroutine
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Some
programming language
may
group multiple
functions into
larger units; e.g.: a
class in
Python !
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