Control Structures
if/else
if (boolean) {} else if {} else {}
while
while (boolean) {}
for
for x from a to b by c
is the general case. You don't need to specify whether it's going up or down - although doing so by using upto or downto does allow a runtime check to make sure you didn't screw up.
If you don't specify "c", it defaults to incrementing/decrementing by 1.