神马品牌网美国和朝鲜开战的电影:计算机英语文章翻译..希望高手帮下忙~~~谢谢了~(2)
来源：百度文库 编辑：神马品牌网 时间：2024/04/27 23:10:20
A given input/output relation may be realized by a wide bariety of different algorithms. and each algorithm may in turn be realized in a variety of different programming languages.There is thus considerable freedom in developing a program for the solution of any given problem. This freedom of choice in developing program leads to the notion that programming is an art rather than a scioncc.
Although the set of all programs for realizing a given problem specification is in general infinite, there are a number of critcria other than correctness which may be used to restrict the class of acceptable programs that realize a given problem specification. A good program should economize both on computation time and on the storage space required to repressent the program and data structures. It should have a modular structure in the sense that each well-defined subtask should be specified by a well-defined subprogram. Modular design of a program is important because it makes the program easier to understand,facilitates debugging, and allows modifications to be made more easily. It is usually worth paying a price in computation time and momory space in order to achieve greater modularity. Modular construction is especially important in large programs, since the human mind is severely restricted in the complexity it can handle, and systcmatic modularity reduces the number of factors the human mind must handle at any given moment, thereby allowing the understanding of a larger system than would otherwise be possible.
Programming was regarded as an art rather than a science in the 1950s and 1960s because it was felt that the choices among different styles of implementing a given problem were creative choices based on intangible criteria of style just as in the case of literalure. However, as more experience was gained in writing large programs, the freedom of the programmer,to develop a personal style became increasingly restricted by programming conmventions designed to mechanize programming style. For example, it has become accepted that go to statements, should be more heavily used.
During the last few years, it has been realized that maintenance of programs is more expensive than development,so reading of programs by humans is as important as writing them. Documentation and other aids to readability are becoming increasingly important. The programs of a large system are increasingly viewed as one of several forms of system documentation and are stored in a database for maniputlation by compilers and other system programming tools.
Although the set of all programs for realizing a given problem specification is in general infinite, there are a number of critcria other than correctness which may be used to restrict the class of acceptable programs that realize a given problem specification. A good program should economize both on computation time and on the storage space required to repressent the program and data structures. It should have a modular structure in the sense that each well-defined subtask should be specified by a well-defined subprogram. Modular design of a program is important because it makes the program easier to understand,facilitates debugging, and allows modifications to be made more easily. It is usually worth paying a price in computation time and momory space in order to achieve greater modularity. Modular construction is especially important in large programs, since the human mind is severely restricted in the complexity it can handle, and systcmatic modularity reduces the number of factors the human mind must handle at any given moment, thereby allowing the understanding of a larger system than would otherwise be possible.
Programming was regarded as an art rather than a science in the 1950s and 1960s because it was felt that the choices among different styles of implementing a given problem were creative choices based on intangible criteria of style just as in the case of literalure. However, as more experience was gained in writing large programs, the freedom of the programmer,to develop a personal style became increasingly restricted by programming conmventions designed to mechanize programming style. For example, it has become accepted that go to statements, should be more heavily used.
During the last few years, it has been realized that maintenance of programs is more expensive than development,so reading of programs by humans is as important as writing them. Documentation and other aids to readability are becoming increasingly important. The programs of a large system are increasingly viewed as one of several forms of system documentation and are stored in a database for maniputlation by compilers and other system programming tools.
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