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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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