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Which of the following is not a valid C++ identifier?

A. _variableName

B. 2ndVariable

C. variable_name@

D. VariableName

E. Both (B) and (C)

Answer: Option E

Solution (By Examveda Team)

C++ Identifiers: Naming Rules
In C++, identifiers are names you give to things like variables, functions, and classes. They must follow specific rules.

Rules for Valid Identifiers:
1. They can contain letters (a-z, A-Z), digits (0-9), and underscores (_).
2. They must begin with a letter or an underscore.
3. They cannot contain spaces.
4. They cannot be C++ keywords (like int, float, while, etc.).

Let's Check the Options:
A) _variableName: This is valid. It starts with an underscore and uses letters.
B) 2ndVariable: This is invalid. Identifiers cannot start with a digit.
C) variable_name@: This is invalid. It contains the "@" symbol, which is not allowed.
D) VariableName: This is valid. It starts with a letter and uses letters.

Therefore, the correct answer is E, Both (B) and (C) are not valid C++ identifiers.

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Comments (1)

  1. Bhawna Wadhwa
    Bhawna Wadhwa:
    10 months ago

    Sir plz check valid identifier. 2 identifier galat h isme
    Sir ek ek number ki value hoti h.
    Questions bahut ache h lakin ek answer galat ho to sab dusri site search karte h
    Plz 🙏 h iska andwers update kre ya reason de

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