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Q
[Arrays, Strings]

Passwords are stored as two Strings:

StringA → Password entered by the user

StringB → Password stored in the system

If StringA must be checked with StringB for validity, which one of the following String functions should be used?

ID: #24940 Competency focused Practice Questions ISC Class XII Computer Science 8 views

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#24940Q ID

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Competency focused Practice Questions ISC Class XII Computer ScienceTopic

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A charAt() ✔ ✖
B equals() ✔ ✖
C equalsIgnoreCase() ✔ ✖
D startsWith() ✔ ✖

Correct Answer: Option B

Explanation

[Arrays, Strings]

Passwords are stored as two Strings:

StringA → Password entered by the user
StringB → Password stored in the system

If StringA must be checked with StringB for validity, which one of the following String functions should be used?

(a) charAt()

(b) equals()

(d) startsWith()

Correct Answer: (b) equals()

Explanation:

In Java, passwords are usually stored as Strings. To verify a password, the system must compare:

User entered password → StringA
Stored password → StringB

Password comparison must be:

Exact
Case-sensitive
Character-by-character identical

Why equals() is Correct?

The equals() method compares the complete contents of two strings exactly.

StringA.equals(StringB)

It returns:

true → if both strings are exactly same
false → if there is any difference

Example:

StringA = "Admin123"
StringB = "Admin123"

Result = true

StringA = "admin123"
StringB = "Admin123"

Result = false

Why Other Options are Wrong?

Method	Reason
charAt()	Returns only a single character at a specific position. It cannot compare complete passwords.
equalsIgnoreCase()	Ignores uppercase and lowercase differences. Passwords should normally be case-sensitive for security.
startsWith()	Checks only whether a string starts with another string. It does not compare the complete password.

Conclusion:

Since password validation requires exact matching, the correct method is:

equals()

Therefore, the correct answer is: (b) equals()

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Q [Arrays, Strings] Passwords are stored as two Strings: StringA → Password entered by the user StringB → Password stored in the system If StringA must be checked with StringB for validity, which one of the following String functions should be used?