Boolean values

From Rosetta Code
Revision as of 17:57, 10 July 2009 by rosettacode>Mwn3d (Should have previewed)
Task
Boolean values
You are encouraged to solve this task according to the task description, using any language you may know.

Show how to represent the boolean states "true" and "false" in a language. If other objects represent "true" or "false" in conditionals, note it.

BASIC

Works with: QuickBasic version 4.5

QuickBasic has no keywords for true and false. Boolean expressions evaluate to 0 when false, and a non-zero value when true. Numbers also work in place of boolean expressions following those rules.

Java

Java has true and false keywords. There are also object wrappers Boolean.TRUE and Boolean.FALSE which act in the same places, but have methods defined for them.

Ruby

The only values in Ruby that are false are: false and nil. They have synonyms FALSE and NIL.

Everything else (including the number 0 and the empty string) is true. Constants true (and TRUE) exist.