7-2
Algorithms and programming
7-2-1 Data structures
When developing a system, programs must be created so that the necessary functions will operate correctly. Here, the data structures and algorithms required during programming will be explained.
1
Data and data structures
“Data” is defined as the information manipulated internally by a computer. When a collection of data is systematically organized and managed as
a group, that information is known as a “data structure.”
Data structure design serves as the entire foundation of system development. Accordingly, it is necessary to plan and investigate data structures
ahead of time so that they can execute the desired tasks.
The fundamental data structures are summarized below.
Reference
Constant
A “constant” is data possessing a certain fixed value. They are the opposite
of variables.
●Variables
A “variable” identifies the location where data currently used by programs
is stored temporarily. When defining a variable, a variable name consisting
of alphanumeric characters and symbols is entered to differentiate it from
other data. In addition, while it is being used, the variable is assigned a
value.
For example, in the expression “y = a + 10,” by assigning a value of “10”
to a, y will equal “20.” Since the properties of variables allow for different
values to be entered each time a program is executed, there is no need to
rewrite the actual program at such times.
10
y=
Data is assigned when the program is executed.
a
+10
The variable acts as a kind of box which contains the data.
171