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// Simple sine function implementation - no lib's req.
// Forward declarations for cosine(..)
double
powerd( double x,
int y);
double
factorial_div( double value,
int x);
double
cosine( double x);
/********************************************************************************/
/*
*/
/* cosine(
x) */
/*
*/
/********************************************************************************/
double
cosine( double x)
{
int i=0;
int j=1;
int sign =1;
double y1 = 0.0;
double diff = 1000.0;
if( x < 0) x = -1 * x;
while ( x > 360.0*3.1415926/180)
{
x = x - 360*3.1415926/180;
}
if( x > (270 * (3.1415926/180)) )
{
x = 360 * (3.1415926/180) - x;
}
if( x > (180 * (3.1415926/180)) )
{
sign = -1;
x = x - 180 * (3.1415926/180);
}
if( x > (90 * (3.1415926/180)) )
{
sign = -1;
x = 180 * (3.1415926/180) - x;
}//
End if(..)
while( powerd( diff, 2) > 1.0E-16 )
{
i++;
diff = j * factorial_div( powerd( x, (2*i -2)) , (2*i -2));
y1 = y1 + diff;
j = -1 * j;
}//
End while(..)
return (y1*sign);
}//
End cosine(..)
/********************************************************************************/
/*
*/
/* powerd( x, power
) */
/*
*/
/********************************************************************************/
double
powerd( double x,
int y)
{
int i=0;
double ans=1.0;
if(y==0) return
1.000;
else
{
while( i < y)
{
i++;
ans = ans * x;
}// End while(..)
}//
End else
return ans;
}//
End powerd(..)
/********************************************************************************/
/*
*/
/* factorial( x
) */
/*
*/
/********************************************************************************/
double
factorial_div( double value,
int x)
{
if(x == 0) return
1;
else
{
while( x > 1)
{
value = value / x--;
}// End while(..)
}//
End else
return value;
}//
End factorial_div(..)
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