|
|
General Characteristics of Programming
Generations of programming languages.>
Programming languages fall into two fundamental categories-low and high-level languages. Low-level languages are machine-dependent; that is, they are designed to be run on a particular computer. In contrast, high-level languages (for example, COBOL and BASIC) are machine-independent and can be run on a variety of computers.
The hierarchy of programming languages in the Figure summarizes the relationships between the various types of programming languages. Through the first four decades of computing, programming languages evolved in generations. The first two generations were low-level and the next two high-level generations of programming languages.
The higher-level languages do not provide us a greater programming capabilities, but they do provide a more sophisticated programmer/computer interaction. In short, the higher the level of the language, the easier it is to understand and use. For example, in a fourth-generation language you need only instruct the computer system what to do, not necessarily how to do it.
When programming in one of the first three generations of languages, you have to tell the computer what to do and how to do it. What comprises a new generation is less clear; therefore, languages after the fourth generation are referred to as a very high level languages.
