Aif (x>0) y=1;
else if(x<0)y=-1;
else y=0;

Bif(x)
if(x>0)y=1;
else if(x<0)y=-1;
else y=0;

Cy=-1
if(x)
if(x>0)y=1;
else if(x==0)y=0;
else y=-1;

Dy=0;
if(x>=0)
if(x>0)y=1;
else y=-1;