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High-Level Language (HLL)
High-level language is designed to be easier for humans to write and understand. It is
machine-independent. However, they need to be translated into binary or machine language.
Programs written in high-level languages are called source code. Since the computer
understands only 0s and 1s, all high-level languages require a software called language
processor or translator to convert the instructions written in HLL into machine language.
There are three main categories of high-level languages, which are third generation languages,
fourth generation languages, and natural languages.
Third Generation Languages (3GL)
In third generation languages (3GL), the programmer writes a series of English-like words that
tell the computer what to accomplish and how to do it. It is more like human language than
machine language.
Many third generation languages also use arithmetic operators such as * for multiplication and
+ for addition. These English-like words and arithmetic notations make it easy for a programmer
to write the programs. Some early procedural 3GLs are BASIC, PASCAL, C, and FORTRAN. Some
other advanced object-oriented 3GLs are C++, Java, and C#.
Fourth Generation Languages (4GL)
The fourth generation languages also use English-like statements. They specify what the
program should accomplish without explaining how. 4GL is fast and requires less time and
effort on the part of the programmer. In fact, 4GLs are so easy to use that programmers with
very little programming background can develop programs using them. Examples of 4GL are
SQL, Perl, Prolog, Python, etc.
Natural Languages (5GL)
The fifth-generation languages, also known as natural languages, are the programming
languages that have visual tools to develop a program. They are based on artificial intelligence
(AI) principles and are designed to help computers learn to solve problems.
Examples of fifth generation languages include Mercury and OPS5.
Natural language is very easy to use. For example, if a program is written in 4GL to get the
names of students whose marks exceed 95, it might be written as:
SELECT LAST-NAME, FIRST-NAME FROM STUDENT WHERE MARKS > 95.
A natural language version of the same program might be written as:
TELL ME THE NAME OF STUDENTS WITH MARKS OVER 95.
These systems are popular in the medical and scientific fields, but are not widely used in business
applications.
Advantages of High-Level Languages
• A high-level language is user-friendly.
• A high-level language is similar to the English language with its vocabulary of words and
symbols, therefore it is easier to run.
• A high-level language requires less time to write a program.
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