static qatan2(); atan2(xx, yy){ register x, y; x=abs(xx); y=abs(yy); if(xx>=0 && yy>=0) return(qatan2(x, y)); if(xx<0 && yy<=0) return(180+qatan2(x, y)); if(xx<0 && yy>0) return(180-qatan2(x, y)); return(360-qatan2(x, y)); } static qatan2(x, y) register x, y; { if(x<y) return(90-(45*((long)x)/y)); if(y==0) return(0); return(45*((long)y)/x); }