Relational Operators (Objective 7.6)
- Relational operators always result in a boolean value (true or false).
- There are six relational operators: >, >=, <, <=, ==, and !=.
- The last two (== and !=) are sometimes referred to as equality operators.
- When comparing characters, Java uses the Unicode value of the character as the numerical value.
- There are two equality operators: == and != .
- Four types of things can be tested: numbers, characters, booleans, and reference variables.
- When comparing reference variables, == returns true only if both references refer to the same object.
- instanceof is for reference variables only, and checks for whether the object is of a particular type.
- The instanceof operator can be used only to test objects (or null) against class types that are in the same class hierarchy.
- For interfaces, an object passes the instanceof test if any of its superclasses implement the interface on the right side of the instanceof operator.
- There are four primary math operators: add, subtract, multiply, and divide.
- The remainder operator (%), returns the remainder of a division.
- Expressions are evaluated from left to right, unless you add parentheses, or unless some operators in the expression have higher precedence than others.
- The *, /, and % operators have higher precedence than + and -.
- If either operand is a String, the + operator concatenates the operands.
- If both operands are numeric, the + operator adds the operands.
- Prefix operators (++ and --) run before the value is used in the expression.
- Postfix operators (++ and --) run after the value is used in the expression.
- In any expression, both operands are fully evaluated before the operator is applied.
- Variables marked final cannot be incremented or decremented.
- Returns one of two values based on whether a boolean expression is true or false.
- Returns the value after the ? if the expression is true.
- Returns the value after the : if the expression is false.
- The exam covers six "logical" operators: &, |, ^, !, &&, and ||.
- Logical operators work with two expressions (except for !) that must resolve to boolean values.
- The && and & operators return true only if both operands are true.
- The || and | operators return true if either or both operands are true.
- The && and || operators are known as short-circuit operators.
- The && operator does not evaluate the right operand if the left operand is false.
- The || does not evaluate the right operand if the left operand is true.
- The & and | operators always evaluate both operands.
- The ^ operator (called the "logical XOR"), returns true if exactly one operand is true.
- The ! operator (called the "inversion" operator), returns the opposite value of the boolean operand it precedes.
regards,
Agni..
Executive,
Talent Sprint
Hyderabad.
for Feedback and Support simply drop a mail in
agni2020{at}gmail.com
Remember to replace the {at} with @ in the email addresses
No comments:
Post a Comment