! (logical NOT)

Inverts the Boolean value of an expression. Returns true if the expression is false and returns false if the expression is true. If the expression (a>b) evaluates to true, then !(a>b) evaluates to false.

• size(400, 400);
  boolean a = false;
  if (!a) {
   rect(120, 80, 200, 200);
  }
  if (a) {
   line(80, 40, 360, 320);
   line(80, 320, 360, 40);
  }

  👁 Image
  

• size(400, 400);
  boolean a = true;
  if (!a) {
   rect(120, 80, 200, 200);
  }
  if (a) {
   line(80, 40, 360, 320);
   line(80, 320, 360, 40);
  }

  👁 Image
  

• !expression

• expressionany valid expression

• logicalAND
• logicalOR
• if