Introduction - If you have any usage issues, please Google them yourself
[Example 6.13] the trapezoidal method to seek the integral function integer () is a universal function, rectifiable any definite integral of a function. Different functions have different analytical formula
//Parse type determines the value of the function of independent variables in each small integral interval endpoints. Function integer () to a pointer to a function as a parameter,
//Desire definite integral function is called by the parameters, the other two parameters are the limits of integration.