第三周项目2—太乐了

#include <iostream>
using namespace std;
const double pi=3.1415926;
double mysin(double);
double myabs(double);
int main( )
{
    cout<<"sin(π/2)的值为"<<mysin(pi/2)<<endl;
    cout<<"sin(56°)的值为"<<mysin((56.0/180)*pi)<<endl;
   return 0;
}

double mysin(double x)
{
    double sum=x,num=x,term;
    int n=1,den=1,sign=1;
   do
    {
        den=den*(n+1)*(n+2);
        num=x*x*num;
        sign=-sign;
        term =num/den*sign;
        sum=term+sum;
        n=n+2;
    }
    while(myabs(term)>1e-5);
    return sum;
}

double myabs(double x)
{
    return ((x>=0)?x:-x);
}

运行结果：

知识点总结：自定义函数解决问题

学习心得：数学是硬伤啊