本示例中使用了面向对象的程序设计方法，通过对()运算符的重载，把求积运算符号写成(a,b,eps),表示对一个函数从a到b的积分，其中eps是精度。为了显示面向对象的强大之处，我写了两个被积函数，只要直接继承那个被积函数抽象类并覆盖其方法即可。-This example uses the object-oriented programming approach, through the () operator overloading, the quadrature operation symbols written (a, b, eps), expressed as a function of the integral from a to b, where eps is accuracy. To show the power of object-oriented, I wrote two functions are integrated, as long as the direct successor to the integrand abstract class and override its methods can be.