说明：  用PHP编写的表达式计算器，是用的编译的知识实现的，并非使用eval()函数实现。 功能强大，可以做所有的数值计算，代数计算还不能实现。 1。可以计算形如“-3*sin(2^0.5/2+3.1415)-pi()^2”的式子。 2。能识别数字（包括小数、正负数）、数学函数。 3。可以做加、减、乘、除、指数、取模 计算（其中加、减包括一元和二元两种操作）。 压缩包里的“math.php”是演示文件
(with PHP prepared by the expression calculators, is the translation of knowledge to achieve, and are not using eval () function to achieve. Powerful, can do all the numerical calculation, algebraic calculations also can not be achieved. 1. Shape can be calculated as "-3* sin (2 ^ 0.5/2 3.1415)- pi () ^ 2" formula. 2. Can identify figures (including decimal, plus or minus a few), math functions. 3. Can do, plus or minus, multiplication, addition, the index, calculated from model (which, plus or minus one yuan and include both binary operation). Compression bundle "math.php" Presentations)