where is my mistake

[sisqu]

Hi,
First I want to show you what I read in book and apply in this programme.
I want to write a programme for manage a cutting machine. For this I need a cicle for, whitch I count points by moving into circle. In book i read:
represent a sircle x=RcosA+x0;
y=RsinA+y0;
where: x0,y0 coordinates of center of circle,
R radius
or if I use integrale arithmetic: dx=-RsinAda dy=RcosAda
follow this:RcosA=x-x0, RsinA=y-y0;
so: dx=-(y-y0)da
dy=(x-x0)da

That means that I would use this extenses for count points:
x2=x1+dx=x1-(y1-y0)da
y2=y1+dy=y1+(x2-x0)da
In cutting machine I have first point x1, y1 present point x2,y2
and distance between first point x1,y1 and center of circlex0,y0
I and j t.e. x-x0=I, y-y0=J. And this programme must give points to moving by clockwise begin from x=0, y=10 (angle=90 degree) and stop when angle=45 degree(0,78 rad) instead it give points if it moves contraclock wise.
I wander if i'm wrong or the book wrong?

double wmin(double a1,double a2);

int main(void) {

int in=0;
double adrawn=0.00,x=0.00,y=10.00;
//adrawn-angle by moving, x y begin points
double xar=0.00,yar=10.00,i=0,j=10,da;
//* xar, yar present points; i and j distance between first point and center of circle i=x-x0, j=y-y0 */
da=wmin(0.01,1/(3.2*(i+j)));
//da=0,017453292

for(adrawn=0.00;adrawn<=0.785398163;adrawn=adrawn+da) {

xar=xar+(y-j-yar)*da;
yar=yar+(xar-x+i)*da;
printf(&quot; x=%f y=%f&quot;,xar,yar);
}

return 0;
}

double wmin(double a1,double a2) {
if(a1>a2) return a2;
return a1;
}
Thank you very much

 

[apatterno]

faq116-3426

Will

 

[Robinhood361]

use
xar=xar-(y-j-yar)*da;

instead of

xar=xar+(y-j-yar)*da;

in the FOR loop
Just check for the formula the book has used