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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. Many third generation languages also use
arithmetic operators such as * for multiplication and + for addition. Some early procedural 3GL
are BASIC, PASCAL, C and FORTRAN. Some other advanced object-oriented 3GL 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. A 4GL is fast and requires less time and effort on the part
of the programmer. In fact, 4GLs are so easy to use and programmers with very little programming
background can develop programs. Examples of 4GL are SQL, Perl, 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. Examples of fifth generation language include Mercury,
OPS5, and Prolog. Natural language is very easy to use. Natural languages are often associated with
expert system and artificial intelligence.
LANGUAGE TRANSLATOR
A language translator is a software that converts a high-level language program into a machine
language. There are three types of language translators.
Assembler
An assembler is a program used to translate assembly language into machine language so that the
computer can understand it. The assembler enables the computer to convert the assembly language
instructions into machine code, i.e., 0’s and 1’s.
Compiler
A compiler is a software that converts the entire source program into machine language before
executing it. It converts the entire high-level language program into machine language at once. It
displays the errors for the whole program together.
Interpreter
An interpreter is also a separate program that converts the entire source program into machine
language before executing it. It translates and executes one statement at a time. It displays the errors
one line at a time and it goes to the next line only after the error is corrected.
Introduction to Programming 99

