实现类似Windows操作系统“计算器”的功能。可以完成任意的通常借助手持计算器来完成的标准运算。“计算器”可用于基本的算术运算，比如加减运算等。同时它还具有科学计算器的功能，比如对数运算和阶乘运算等。-Windows operating system to achieve a similar " calculator"　function. You can complete the usual arbitrary use handheld calculators to complete the standard operation. " Calculator"　can be used for basic arithmetic operations, such as addition and subtraction operations. It also has a scientific calculator functions, such as arithmetic and logarithmic factorial computing.