Thread: problem function Sin()

i have wrote function Sin(), didn'd use math in libary, but when it run the result error, can you help me? fix it thanks very much.
sin(x)=Tn((-1)^k )*(x^2k+1)/(2k+1)!

Code:

#include <iostream>
using namespace std;

double gt(double d){
	if(d==1||d==0)return 1;
	return d*gt(d-1);
}
//
double power(double a, int b)
{
      double c=1;
      for (int h=0; h<b; h++) c*=a;
      return c;
}
//
double Mysin(int x){
	double Sum=0;
	for(int i=1;i<=10;i++){
		double tmp=gt(2*i+1);
		Sum+=(power(-1,i)*(power(x,2*i+1)))/tmp;
	}
	return Sum;
}
void main(){
	//MySin M;
	int x;
	cin>>x;
	cout<<Mysin(x);
}