Conditional Statements

The Boolean Type

• boolean is another primitive type
• There are two boolean constants: true and false
• There are several operators that produce boolean (true/false) results. The simplest are:

  Operator	Example	Meaning
  ==	i == k	equals? (same values?)
  !=	i != 0	not equal to?
  <	i < 0	less than?
  <=	i <= k	less than or equal to?
  >	i > 0	greater than?
  >=	i >= k	greater than or equal to?

• Methods can return boolean values. For example, the method call fish.atWall() will return true if the fish is at the wall (and facing the wall), and will return false otherwise. (See the AquaFish class documentation.)
• We can also have boolean variables. For example,

      int i = 2;
      int k = 3;
      boolean same = i == k;               // same will be false
      boolean iIsSmaller = i < k;          // iIsSmaller will be true
  
      boolean isAtWall = fish.atWall();    // isAtWall will be true if the
                                           // fish is at the wall
  

boolean expressions are frequently used in conditional statements (next topic).