求sin三角函数

#include<iostream>
using namespace std;
double mysin(double);
double myabs(double);
const double pi=3.1415926;
int main()
{
    cout<<"sin(pi/2)的值"<<mysin(pi/2)<<endl;
    cout<<"sin(56)的值"<<mysin(myabs(56))<<endl;

}

 double mysin(double a)
{
    double myabs(double);
    double sum=0,b=1,d;
    int n=1,m=1,c=1,q=-1;
    do
    {

      for(d=1;n<=m;++n)
      {
        d=d*a;
        c=c*n;
      }
      n=1;
      q=q*(-1);
      b=q*(d/c);
      sum=sum+b;
      m=m+2;
       d=1;
      c=1;
    }while(b>0.00001||b<-0.00001);
    return(sum);
}

double myabs(double s)
{
double    pi=3.1415926;
    s=(s/180);
    s=s*pi;
    return(s);

}