# include <iostream>
# include <math.h>
using namespace std;
double sin_value( double x);
double x;
double value;
int main()
{
cout << "Welcome!";
cout << "Let's calculate sine value. " << endl;
cout << "Enter value x: ";
cin >> x;
value = sin_value(x);
cout << "The value is: ";
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(10);
cout << value;
return 0;
}
double sin_value( double x)
{
int count=1;
double sine, num, dem, sign, term;
sine=0;
sign = 1;
num = x;
dem = count;
while ( count <= 20 )
{
term = (num/dem);
sine = sine + term*sign;
num = num*x*x;
count = count + 2;
dem = dem * count * (count-1);
sign = -sign;
}
return (sine);
}