1.选择任意方法完成简单计算器的设计任务，最终输出计算器计算的结果。

写出算术表达式的符合分析方法要求的文法，给出分析方法的思想，完成分析程序设计。编制好分析程序后，设计若干用例，上机测试并通过所设计的分析程序。此处上传的实现的原理。-1 Select any way to complete a simple calculator design task, the final output of calculator results. Write arithmetic expressions in line with the requirements of grammar analysis, analysis of the ideas given to complete the analysis of program design. After the preparation of a good analysis program, designed a number of use cases, the machine test and analysis through the design process.