def reverse( x )
	( x.length / 2 ).times { |i|
		work = x[ x.length-1-i ]
		x[ x.length-1-i ] = x[ i ]
		x[ i ] = work
	}
end

a = [ 3 , 6 , 2 , 4 , 10 , 7 ]
reverse( a )

a.length.times { |i|
	printf( "%d " , a[ i ] )
}
printf( "\n" )