Question

Identify the identifiers as valid or invalid (reason if invalid) i. break ii. Program 1​

Answer 1

Answer:

i) invalid (reserved keyword)

ii) valid

Explanation:

Rules for identifier:

• A valid identifier must have characters [A-Z] or [a-z] or numbers [0-9], and underscore(_) or a dollar sign ($).

• There should not be any space in an identifier.

• An identifier should not contain a number at the starting.

• We can't use the Java reserved keywords as an identifier such as int, float, double, char, etc.

• An identifier should not be any query language keywords such as SELECT, FROM, COUNT, DELETE, etc.

List of Valid identifiers:

1. xyz

2. fvariable

3. a

4. cal_sum

5. _product

6. $money

7. variable123

8. num

9. thisIsMe

10. hello_Me1

Refer to the attachment to see the list of reserved keywords(cannot be used as identifier).

Answer 2

Hey

Here's your answer

Rules for Identifiers:

1. The only allowed characters for identifiers are all alphanumeric characters([A-Z],[a-z],[0-9]), ‘$‘(dollar sign) and ‘_‘ (underscore).

2. Identifiers should not start with digits([0-9]).

3 . Java identifiers are case-sensitive.

4. There is no limit on the length of the identifier but it is advisable to use an optimum length of 4 – 15 letters only.

5.Reserved Words can’t be used as an identifier.

6. An identifier should not have a space.

Back to the question:

i) break - invalid

Reason: break is a reserved keyword, identifiers can't be a reserved keyword.

ii) Program 1 - invalid

Reason: Identifier cannot have a space.