3.5-Relational, Comparisson & Logical Operators

Question 1

📝️ What are the Comparisson operators?

Answer 1

== | != -> Operators that can be used to check equality

-> Are the same? | Are different values?
🤯️⚠️📣️ There’s a semantic difference between:
-> “Two objects are the same” and…
-> “Two objects are equivalent.”

👀️🧠️ However for numeric and boolean primitives, there is no such distinction.

Question 2

What are the four scenarios for comparisson operators? and what are its PITFALL cases?

Answer 2

[SCENARIOS
1°  boolean type operands
2° numeric primitive types operands
3° char primitive types operands
4° Reference types operands

[PITFALLS]
🤯️⚠️📣️ We cannot mix and match types 
   ❌true == 3 | ❌false != "Grape" | ❌10.2 == "Koko" //DOES NOT COMPILE
However...
✅ 5 == 5.0

🤯️⚠️📣️ Two references are equal only if they point to the same object or both point to null.

🤯️⚠️📣️ Comparing null with other null value return true -> (null == null) //RETURNS TRUE

Question 3

What are the Relational operators and its PITFALL case(s)?

Answer 3

[PRECEDENCE]
>, >=, < , <= , instanceof

[PITFALLS]
🤯️⚠️📣️ If null is used on the left side of the instanceof operator it returns FALSE

❌The code won’t compile❌
🤖️ If null is used on the right side of the instanceof operator
🤖️ If left-type cannot possibly hold right-type ❌The code won’t compile❌
e.g: Integer instanceOf String

Question 4

What are the logical operators and its precedence?

Answer 4

(Bitwise | Logical Operators)

&, |, ^, &&, ||

Question 5

📝️ What are the logical operators behavior?

Answer 5

& AND is only true if both operands are true.
| Inclusive OR is only false if both operands are false.
^ Exclusive OR is only true if the operands are different.

Question 6

What are the short-circuit Logical operators?

Answer 6

&&, ||

📝️ What does short-circuit means? The second operand is evaluated only if required.