Evolution of Programming Languages
Most books and articles on history of programming languages tend to discuss languages in term of generations.This is useful arrangement for classifying languages by age.I agree that whatever a few of we ‘more mature’ software engineers get together, we cannot ever seem to agree on wht constitutes the generation of computer languages.We know that Formula Translation (FORTRAN) was probably a first-generation languges.Does that make FORTRAN 77 and WatFor second languages?Is the newest FORTRAN (FORTRAN 90) third or fourth generation?How about commom Bussiness-Oriented Languages (COBAL)?It has been arround since 1959, and yet COBAL 2000 will be an object-oriented(OO)COBAL.Does this make it fourth generation or is it still first generation?
The first generation programming languages is machine language,which required the use of binary symbols (0s and 1s).Because this is the language of the CPU,text file hat is translated into binary sets can be reas by almost every computer syatem platform.Originally no translator was used to change he source code into object code.
Developers of programmeing languages attempted to overcome some of the difficulties inherent in machine languages by replacing the binary digits with symbols that programmers could more easily understand.These second-generation languages use code like A for add, MCV for move, and so on.Another term for these languages in assembly languages, which comes from the programes (called assemblers) used to translate into machine code.System software programs such as Oss and utility programes are often written is an assembly languages.
Third-Generation languages continued the trend toward greater use of symbolic code and away from specifically instructing the computer how to complete an operation, BASIC, COBOL, C and FORTRAN are examples of third-generation languages that use English and Assembly languages because it more clearly resembles everyday human communication and understanding.
With third-generation and-level programming languages, each statement in the languages translates into several instructions in the machine languages.A special software program called a compiler converts he programmers’s source into the machine-languages instructions consisting of binary digits.A compiler creates a two-stage process for problem execution.First, it translates the program into machine language; second, the CPU executes that program.Another approach is to use interpreter, which is a language translator that converts each statement in progamming language into machine language and executes he statement, one at a time.An interpreter does not produce a complete machine-language program.After the statement executes, the machine language statement is discarded, the process continues for the next statement, and so on.
Fourth-generation programming languages emphasize what output results are desired rather than how programming statement are to be written.As a result, many managers and executives with little or so no training in computers programming are using fourth-generation languages (4GLs).Languages for accesing information in a database are often fourth-generation languages. Prime examples include PowerBuilder, Delpi, Essbase, Forte, Focus, Powerhouse, SAS, many other.Natural is a 4GL that can e used with Windows, UNIX, or Linux.Another popular fourth-generation languages is called Strucured Query Language (SQL), which is often used to perform database queries and manipulations.
Ada Lovelace and baggage and its nephew were writing programs for the project of “difference engine”, and then the “analytical engine”.In 1945, the german K. Zuse, inventor of the Z3 computer would have defined an evolved language for this engine (wih arrays and records). Few documents of the epoch about this language exit.
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