英语翻译
The design phase defines how the system will accomplish what was defined in the analysis phase.In the design phase,the system are determined,and the design of the files and/or the datebases is completed.
Today,the design phase uses a very well-established principle called modularity.The whole package is divided into small modules.Each module is designed and tested and is linked to other modules through a main program.
The design phase uses several tools,the most common being a structure chart.A structure chart shows how to break your package into logical steps;each step is a separate module.The structure chart also shows the interaction between all the parts(modules).
In the implementation phase,you create the actual programs.
This phase uses several tools to show the logical flow of the programs before the actual writing of code.One tool,still popular,is the flowchart.A flowchart uses standard graphical symbols to represent the logical flow of data through a module.
The second tool used by programmers is pseudocode.Pseudocode is part English and part program logic that describes,in precise algorithmic detail,what the program is to do.This requires defining the steps in sufficient detail so that conversion to a computer program can be accomplished easily.