Here is a listing of C Objective Questions on “Variable Names” along with answers, explanations and/or solutions:
1. C99 standard guarantees uniqueness of __________ characters for internal names.
a) 31
b) 63
c) 12
d) 14
Answer: b
Clarification: ISO C99 compiler may consider only first 63 characters for internal names.
2. C99 standard guarantees uniqueness of ___________ characters for external names.
a) 31
b) 6
c) 12
d) 14
Answer: a
Clarification: ISO C99 compiler may consider only first 31 characters for external names.
3. Which of the following is not a valid variable name declaration?
a) int __a3;
b) int __3a;
c) int __A3;
d) None of the mentioned
Answer: d
Clarification: None.
4. Which of the following is not a valid variable name declaration?
a) int _a3;
b) int a_3;
c) int 3_a;
d) int _3a
Answer: c
Clarification: Variable name cannot start with a digit.
5. Why do variable names beginning with the underscore is not encouraged?
a) It is not standardized
b) To avoid conflicts since assemblers and loaders use such names
c) To avoid conflicts since library routines use such names
d) To avoid conflicts with environment variables of an operating system
Answer: c
Clarification: None.
6. All keywords in C are in ____________
a) LowerCase letters
b) UpperCase letters
c) CamelCase letters
d) None of the mentioned
Answer: a
Clarification: None.
7. Variable name resolution (number of significant characters for the uniqueness of variable) depends on ___________
a) Compiler and linker implementations
b) Assemblers and loaders implementations
c) C language
d) None of the mentioned
Answer: a
Clarification: It depends on the standard to which compiler and linkers are adhering.
8. Which of the following is not a valid C variable name?
a) int number;
b) float rate;
c) int variable_count;
d) int $main;
Answer: d
Clarification: Since only underscore and no other special character is allowed in a variable name, it results in an error.
9. Which of the following is true for variable names in C?
a) They can contain alphanumeric characters as well as special characters
b) It is not an error to declare a variable to be one of the keywords(like goto, static)
c) Variable names cannot start with a digit
d) Variable can be of any length
Answer: c
Clarification: According to the syntax for C variable name, it cannot start with a digit.