Forms of if

The if statement can take any of the following forms:
(a) if ( condition )
do this ;
(b) if ( condition )
{
do this ;
and this ;
}
(c) if ( condition )
do this ;
else
do this ;
(d) if ( condition )
{
do this ;
and this ;
}
else
{
do this ;
and this ;
}
(e) if ( condition )
do this ;
else
{
if ( condition )
do this ;
else
{
do this ;
and this ;
}
}
(f) if ( condition )
{
if ( condition )
do this ;
else
{
do this ;
and this ;
}
}
else
do this ;