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Programmers write instructions in various programming languages, some directly understandable by computers and others requiring intermediate translation steps. 

Three general language types:

§Machine languages

§Assembly languages

§High-level languages

Machine Languages

}Any computer can directly understand onlyits own machine language. 

  §This is the computer’s “natural language,” defined by its hard-ware de-sign. 

  §Generally consist of strings of numbers (ultimately reduced to 1s and 0s) that instruct computers to perform their most elementary operations one at a time. 

  §Machine dependent—a particular machine language can beused on only one type of computer.

Assembly Languages

}Englishlike abbreviations that represent elementary operations formed the basis of assembly languages.

}Translator programs called assemblers convert assembly-language programs to machine language.

High-Level Languages 

}High-level languages

  §Single statements accomplish substantial tasks.

  §Compilers convert high-level language programs into machine language. 

  §Allow you to write instructions that look almost like everyday English and contain commonly used mathematical notations. 

}C, C++, Microsoft’s .NET languages (e.g.,Visual Basic, Visual C++ and C#) are among the most widely used high-levelprogramming languages; Java is by far the most widely used. 

}Compiling a high-level language programinto machine language can take a considerable amount of computer time.

}Interpreter programs execute high-level language programs directly, although slower than compiled programs run.

}Java uses a clever mixture of compilation and interpretation to run programs. 

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