One Week summary

This week in class we learned to draw the NS map and pad map, and do a few examples, although the previous data class mentioned Ns,pad diagram, but no systematic talk, learned, after this class of practice so I have a better understanding of NS and pad map.

ns Graphs are also known as box or Chapin diagrams. The flowchart is composed of some specific meanings of graphs, process lines and brief textual descriptions, which can clearly and clearly represent the process of the program. In the process of use, people find that the process line is not necessarily necessary, to this end, people have designed a new flowchart, it writes the entire program in a large block diagram, the large block diagram consists of a number of Small Basic block diagram, which is referred to as NS chart.

and understand the advantages of the NS diagram: It forces the designer to think about the SP method and describe his design, because in addition to representing the symbols of several standard structures, it no longer provides other means of description, which effectively guarantees the quality of the design, thus ensuring the quality of the program;
The NS diagram is intuitive and has good visibility. For example, the scope of the loop, the scope of the condition statement is clear, so easy to understand the design intent, for programming, review, select test cases, maintenance has brought convenience;
NS diagram is simple, easy to learn and easy to use, can be used in software education and other aspects;
The functional domain (that is, the scope of a particular control structure) is clearly defined, and can be intuitively seen from the N-S diagram;
Its control transfer can not be arbitrarily stipulated, must abide by the requirements of structured programming;
It is easy to determine the scope of local data and global data;
It is easy to show nested relationships or to represent the hierarchy of modules.

Several structures of the NS graph: sequential structure, cyclic structure (until the type loop, the loop of the type)

The PAD is an acronym for the Problem Analysis diagram (Problem analytical Diagram) , a graphic presentation tool that has been presented by Ishina and others in Japan since 1974 to describe the detailed design of the software. Like the block diagram, the pad diagram can only describe several basic results that the structured program allows. Since the invention, has been promoted to a certain extent. It uses two-dimensional tree structure diagram to represent the control flow of the program, based on pad diagram, follow the mechanical tree Walk rules can easily write a program, it is easier to convert this diagram to program code.

Pad Chart Features: 1) The structure is clear, the degree of structure is high; 2) easy to read; 3) the leftmost longitudinal line is the program trunk, the first layer of the corresponding program; each additional layer of the pad map to the left to extend a vertical line, the number of lines to help the program is equal to the number of program layers; 4) program execution: from the top Executes from top to bottom, from left to right, and the program terminates at the leftmost main line.

The advantages of PAD diagram: The program structure described in the pad diagram is very clear. The leftmost vertical bar in the diagram is the main line of the program, the first layer of control structure. As the program level increases, the pad map gradually extends to the right, with each additional level, and the graph expands to the right by a vertical line. The total number of bars in the pad chart is the number of levels of the program, and the pad diagram shows the program logic, easy to read, easy to understand and easy to remember. Pad diagram is a two-dimensional tree structure of the graph, the top left side of the program to start execution, top-down, from left to right sequential execution; it is easy to convert the pad diagram into a high-level program language source program, which can be done automatically by software tools, which can eliminate manual coding work, to improve software reliability and software productivity.

One Week summary