It is important that the programmer provide written documentation to support the
program. It is important to the client in understanding the program, and is useful if
updating or further debugging is required. Documentation includes the flowchart, the
pseudocode or narrative description of the program steps, sample input and output
data, an explanation of any techniques use by the programmer, andspecific guidance
needed by the user.
Section II. PROGRAMMING LANGUAGES
2-10. LEVELS OF LANGUAGE
a. General. There are three language levels that programmers may use to
communicate with the computer and to control program execution. These three levels,
machine language, assembly language, and high-level language, have evolved with the
computer and reflect its development toward increasing sophistication. Both machine
and assembly language are considered low-level languages because they are machine-
oriented. They function at extremely fast operating speeds. Even the lowest computer
can work much faster than humans. (Therefore, even if a "slower" high-level language
is used, the computer will still be much faster and more efficient than a human could
be.) Low-level languages share one distinct disadvantage: they are extremely difficult
to learn and decode. For this reason, high-level languages are preferred by
programmers in writing a program.
decode: translate from computer to human language.
b. Machine Language. The oldest language, this is the only one the computer
can execute directly. It is the language of zeros and ones that designates the electrical
states in the computer. Machine language is rarely used to write programs because it is
complex and time-consuming. Each instruction must specify both the operation to be
done and the storage location of data items. It is nontransferable, that is, each type
of computer has its own machine language.
c. Assembly Language. As with machine language, the programmer must
designate both the operation and the storage location of the data. But instead of 0s and
1s, convenient symbols and abbreviations, more easily understood by humans, are
used. "STO", for example, may stand for STORE: TRA" for TRANSFER. Though one
step removed from machine language, it is still difficult to program in assembly
language and, therefore, it is not commonly used for this purpose.