Solving the polynomial of the approximate value of sin (x) of sine function

/* The polynomial formula for the approximate value of the sine sin (x) is known to be:
sin (x) = x-x3/3! + x5/5!-x7/7!+ ... + ( -1) n x2n+1/(2n+1)!  + ... 
*
/#include <stdio.h>
#include <math.h> 
void Main ()
{ 
	int  i; 
	float  x,sum,a,b;  Sum represents and, a is a molecule, B is the denominator 
	char s; 
	printf ("Please input X"); 
	scanf ("%f", &x); 
	S=1; 
	sum=0; 
	a=x;     The denominator assigns the initial value
	b=1;     The numerator assigns the initial value for 
	(i=1;a/b>=1e-6;i++) 
	{  
		sum=sum+s*a/b;    Accumulate a  
	    a=a*x*x;     Seek the next molecule  
	    b=b*2*i* (2*i+1);   Seek the next denominator  
	    s*=-1; 
	}  
	printf ("sum=%f\n", sum);
}