What will be the output of this code?
int counter = 0;
void increment() { static int count = 0; count++; counter++; }
main() { increment(); increment(); printf("%d %d", count, counter); }
Answer: C
The static variable 'count' is local to increment() and inaccessible from main(). Trying to print 'count' causes compilation error: undefined identifier.
Q.182Medium
Which of the following correctly demonstrates function recursion termination?
Answer: B
A base case is essential in recursive functions to provide a stopping condition. Without it, the function will cause stack overflow. The base case ensures recursion terminates properly.
Q.183Medium
What does the const qualifier do when applied to function parameters?
Answer: A
When const is applied to a function parameter, it prevents modification of that parameter within the function body, making it immutable for the duration of the function.
Q.184Medium
Which statement about extern functions is correct?
Answer: B
extern functions have external linkage and can be accessed from other translation units. It's the default linkage for functions declared outside a file.
Q.185Medium
What is the primary purpose of function pointers in C?
Answer: B
Function pointers enable polymorphism by allowing runtime selection of which function to call. They are crucial for implementing callbacks and dynamic function dispatch.
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Q.186Medium
Which of the following is a valid way to return multiple values from a function in C?
Answer: D
C provides multiple methods to return values: structs for encapsulation, pointers for indirect modification, and global variables (though not recommended). All three are technically valid approaches.
Q.187Medium
What happens if a function is declared but never defined in C?
Answer: B
If a function is declared but not defined, the compiler generates code to call it (compilation succeeds), but the linker fails to find the function definition, resulting in a linker error.
Q.188Medium
Consider a function that modifies an array passed as a parameter. Which statement is true?
Answer: B
When an array is passed to a function, it decays to a pointer to its first element. This means modifications to array elements affect the original array outside the function.
Q.189Medium
What is the purpose of function inlining in modern C compilers?
Answer: B
Inlining substitutes a function call with the actual function body at compile time, eliminating function call overhead. This is a compiler optimization for performance-critical code.
Q.190Medium
Which of the following demonstrates proper use of the return statement in error handling?
Answer: D
All three approaches are valid for error handling in C. Functions typically return NULL for pointers, negative values for integers, or use predefined error codes to indicate failure states.
Q.191Medium
A function in C is declared as: int calculate(int *arr, int size). When this function modifies the array elements, what happens to the original array passed from the calling function?
Answer: A
In C, arrays decay to pointers when passed to functions, meaning the address is passed. Any modifications through the pointer affect the original array. This is effectively pass-by-reference behavior for arrays.
Q.192Medium
What will be the output of the following code?
char str[] = "Code";
printf("%c", str[2]);
Answer: C
String "Code" has indices: C(0), o(1), d(2), e(3). str[2] refers to 'd'.
Q.193Medium
What is the difference between char str[] = "Test" and char *str = "Test"?
Answer: B
char[] creates a modifiable array with its own storage. char* points to read-only string literal in memory.
Q.194Medium
Which function is used to reverse a string in C library?
Answer: C
There is no standard library function for string reversal. strrev() is non-standard (available in some compilers). Manual reversal or custom functions are needed.
Q.195Medium
What is the output of the following code?
int arr[] = {10, 20, 30};
printf("%d", sizeof(arr)/sizeof(arr[0]));
Answer: C
sizeof(arr) gives total bytes of array. sizeof(arr[0]) gives bytes of one element. Division gives number of elements: 3.
Q.196Medium
What will be printed by: printf("%s", "Hello\0World");?
Answer: B
\0 is the null terminator which marks the end of a string. %s stops printing at the first null character.
Q.197Medium
Consider: int *ptr = arr; where arr is an array. What does ptr[2] represent?
Answer: B
ptr[2] is equivalent to *(ptr+2), which points to the third element (index 2) of the array.
Q.198Medium
What will the following code output?
char str[20];
strcpy(str, "Competitive");
strcat(str, " Exam");
printf("%s", str);
Answer: C
strcpy copies "Competitive" to str. strcat appends " Exam" to it, resulting in "Competitive Exam".
Q.199Medium
What is the time complexity of searching for an element in an unsorted array of size n?
Answer: C
Linear search on unsorted array requires checking each element in worst case, giving O(n) time complexity.
Q.200Medium
What will be the output of this code?
int arr[5];
for(int i=0; i<5; i++) arr[i] = i*i;
printf("%d %d %d", arr[1], arr[2], arr[4]);
