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This article will explain in detail about the definition of Voss program in PASCAL language, which is divided into several parts. The editor thinks it is very practical, so I share it with you for reference. I hope you can get something after reading this article.

Voss's definition of the program is divided into two parts: algorithm and data structure. The algorithm centrally reflects the process of computer execution, and the data structure is the construction relationship between a large number of data. for the objects processed, the design of a good data structure can greatly simplify the algorithm.

The operating environment of this tutorial: windows7 system, Dell G3 computer.

N.Witrh, the creator of the PASCAL language, gives a concise and precise definition of a program:

Algorithm + data structure = program (Algorithm+Data Structure=Program)

The algorithm centrally reflects the process of computer execution, and the data structure is the construction relationship between a large number of data. for the objects processed, the design of a good data structure can greatly simplify the algorithm. Algorithm and data structure are two important aspects of the program. The description of the data structure in the early programming language is very weak, resulting in the aggravation of the algorithm task. with the development of the language, the ability of data description is gradually enhanced, which is also an important symbol of the development of the language.

Algorithm (Algorithm) refers to the accurate and complete description of the problem-solving scheme, is a series of clear instructions to solve the problem, and the algorithm represents the strategy mechanism to describe the problem-solving in a systematic way. In other words, for a certain standard input, the required output can be obtained in a limited time. If an algorithm is flawed or is not suitable for a problem, executing the algorithm will not solve the problem. Different algorithms may use different time, space or efficiency to accomplish the same task. The advantages and disadvantages of an algorithm can be measured by space complexity and time complexity.

The instruction in the algorithm describes a calculation that starts with an initial state and (possibly empty) initial input, goes through a series of limited and clearly defined states, and finally produces an output and stops at a final state. The transition from one state to another is not necessarily certain. Some algorithms, including randomization algorithms, include some random inputs.

The concept of formal algorithm is partly derived from trying to solve the decision problem proposed by Hilbert and then formed in an attempt to define an effective computational or effective method. These attempts include recursive functions proposed by Kurt Godel, Jacques Herbrand and Stephen Cole Clerney in 1930, 1934 and 1935, λ calculus proposed by Alonzo Church in 1936, Formulation 1 by Emil Leon Post in 1936 and Turing machine by Alan Turing in 1937. Even at present, there are still cases where intuitive ideas are difficult to define as formal algorithms.

Data structure (data structure) is a collection of data elements with structural characteristics, which studies the logical structure of data, the physical structure of data and the relationship between them, defines the appropriate operation for this structure, designs the corresponding algorithm, and ensures that the new structure obtained after these operations still maintains the original structure type. In short, a data structure is a collection of data elements that have one or more specific relationships with each other, that is, a collection of data elements with a "structure". "structure" refers to the relationship between data elements, divided into logical structure and storage structure.

The logical structure and physical structure of data are two closely related aspects of data structure, and the same logical structure can correspond to different storage structures. The design of the algorithm depends on the logical structure of the data, and the implementation of the algorithm depends on the specified storage structure.

The research content of data structure is the foundation of constructing complex software system, and its core technology is decomposition and abstraction. Through decomposition, the data can be divided into three levels; then through abstraction, the specific content of the data elements is discarded, and the logical structure is obtained. Similarly, through decomposition, the processing requirements are divided into various functions, and then the implementation details are abstracted to get the definition of the operation. The combination of the above two aspects can transform the problem into a data structure. This is a process from concrete (that is, concrete problems) to abstract (that is, data structures). Then, the storage structure and implementation operation are further obtained by increasing the consideration of the implementation details, so as to complete the design task. This is a process from abstract (that is, data structure) to concrete (that is, concrete implementation).

This is the end of the article on "Voss's definition of program in PASCAL language is divided into several parts". I hope the above content can be helpful to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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