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); }