$ perl -e 'my $c = 0.5; $c +=1 and printf "%f -> %0.0f\n", $c, $c for 1..10;'
1.500000 -> 2
2.500000 -> 2
3.500000 -> 4
4.500000 -> 4
5.500000 -> 6
6.500000 -> 6
7.500000 -> 8
8.500000 -> 8
9.500000 -> 10
10.500000 -> 10