What happens when you try to access an array element beyond its size in C?
ACompilation error
BRuntime error with exception
CUndefined behavior
DReturns 0 automatically
Correct Answer:
C. Undefined behavior
Explanation:
C does not perform bounds checking on arrays. Accessing beyond array bounds results in undefined behavior - it may access garbage values, crash, or seem to work without error. This is a common source of bugs.
Which of the following is the correct way to pass a string to a function in C?
Avoid func(string s);
Bvoid func(char s[]);
Cvoid func(char *s);
DBoth B and C
Correct Answer:
D. Both B and C
Explanation:
Both char s[] (array notation) and char *s (pointer notation) are valid ways to pass strings to functions in C. C does not have a built-in string type; strings are represented as character arrays or pointers to char.
Which of the following is an invalid identifier in C?
AmyVar
Bmy_var
Cmy$var
D_myVar
Correct Answer:
C. my$var
Explanation:
In C, identifiers can only contain alphanumeric characters (a-z, A-Z, 0-9) and underscores (_), and must start with a letter or underscore. The dollar sign (\() is not allowed, making 'my\)var' invalid.
What will be the output of: int x = 5; printf("%d %d", x++, ++x);?
A5 7
B6 7
C5 6
D6 6
Correct Answer:
A. 5 7
Explanation:
x++ is post-increment (returns 5, then x becomes 6), ++x is pre-increment (x becomes 7, then returns 7). The order of evaluation in printf is implementation-dependent, but typically right to left, giving 5 7.
What is the difference between structure and union in C?
ABoth allocate memory to all members simultaneously
BStructure allocates memory to all members; union allocates shared memory
CUnion allocates memory to all members; structure allocates shared memory
DNo difference
Correct Answer:
B. Structure allocates memory to all members; union allocates shared memory
Explanation:
Structure allocates separate memory for each member (total size = sum of all members). Union shares a single memory location among all members (total size = size of largest member). This is a fundamental difference in memory allocation.
Which of the following function declarations is correct for a function that takes no parameters and returns no value?
Avoid function(void);
Bvoid function();
Cnull function(void);
Dvoid function(null);
Correct Answer:
A. void function(void);
Explanation:
The correct syntax is 'void function(void);' where 'void' in parentheses explicitly states no parameters. Option B is also valid in C (defaults to no parameters), but option A is more explicit and portable across C standards.
Correct Answer:
B. Create an alias for existing data types
Explanation:
typedef creates an alias (synonym) for existing data types. For example, 'typedef int Integer;' creates 'Integer' as an alias for 'int'. This improves code readability and portability. It doesn't create entirely new types, but provides alternative names.
