1.10 Expressions, Assignments, and Operators

Expressions evaluate to values, and are used in assignments or in calls to methods:

Mathematical (result in numerical values)

• 5 + 4
• a - 6
• Math.sqrt(18) * 0.3

Boolean (results in a boolean value)

• (a > b)
• ((a == b) && (c > d))
• (someClass.isValid() == true)

Some special notations exist for incrementing/decrementing:

• i++ , i-- (in-/decrement by one)
• i += 10 , i -= 10 , i *= 10 , i /= 10 (shorthand for operating on the variable and re-assigning the value)

In an assignment, values are stored in a location denoted by a name. The left side of an assignment must necessarily denote a memory location denoted by a variable name. The right side of an assignment must be a value:

• int i = 6
• double d = Math.sqrt(193)
• String s = new String("a useful string")

Operators in Java include:

Mathematical: + , - , * , / , % (modulus)

Boolean: && (and), || (or), == (test equality), != (test inequality