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

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

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

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