In C, what is the purpose of the #define directive?

The correct answer is B: To define macros or constants. #define is a preprocessor directive used to define symbolic constants (macros) and performs text substitution before compilation.

In cybersecurity, what does encryption primarily protect against?

The correct answer is C: Unauthorized access to data during transmission. Encryption converts data into unreadable format, protecting it from unauthorized access during transmission and storage.

What is the output of: printf("%f", 5/2);

The correct answer is B: 2.000000. Since both 5 and 2 are integers, integer division is performed: 5/2 = 2. The %f format specifier then prints this integer value (2) as a floating-point number: 2.000000

Which function is used to read a single character from standard input?

The correct answer is B: getchar(). getchar() reads a single character from standard input (stdin). While fgetc() can also read a character, getchar() is the standard dedicated function for this purpose.

In a B-tree of order m, what is the maximum number of keys that a non-root node can contain?

The correct answer is C: 2m-1. A B-tree of order m can have at most 2m-1 keys in any node and minimum m-1 keys in non-root nodes.

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Q.61 Medium C Programming

What is the output of: int x = 5; int y = ++x; ?

A x = 5, y = 5

B x = 6, y = 6

C x = 6, y = 5

D x = 5, y = 6

Correct Answer: B. x = 6, y = 6

EXPLANATION

The pre-increment operator ++x increments x first (from 5 to 6), then assigns the new value to y. So x = 6 and y = 6.

Test

Q.62 Medium C Programming

What is the output of: int a = 10, b = 20; int *p = &a, *q = &b; printf("%d", *p + *q);?

A 10

B 20

C 30

D Error

Correct Answer: C. 30

EXPLANATION

*p dereferences to a (10) and *q dereferences to b (20). Adding them: 10 + 20 = 30. Pointer arithmetic is used correctly here.

Test

Q.63 Medium C Programming

In the expression: int arr[10]; what is arr[5]?

A A pointer to the 5th element

B The value at memory address arr + 5

C Both A and B are equivalent

D An integer value between 0-10

Correct Answer: C. Both A and B are equivalent

EXPLANATION

arr[5] accesses the element at index 5, which is at memory address (arr + 5). Array name arr acts as a pointer to the first element.

Test

Q.64 Medium C Programming

What is the return type of malloc() function?

A int*

B char*

C void*

D size_t

Correct Answer: C. void*

EXPLANATION

malloc() returns a void pointer (void*), which can be cast to any data type pointer as needed by the programmer.

Test

Q.65 Medium C Programming

What is the purpose of the const keyword when used with a pointer?

A To make the pointer variable unchangeable

B To make the pointed data unchangeable

C Both A and B depending on placement

D To allocate memory in the constant segment

Correct Answer: C. Both A and B depending on placement

EXPLANATION

const int *ptr makes the data constant (const int * ptr). int * const ptr makes the pointer constant. The position of const matters.

Test

Q.66 Medium C Programming

Which of the following correctly uses the ternary operator?

A x = (a > b) : a : b;

B x = (a > b) ? a : b;

C x = a > b ? a : b

D x = (a > b) -> a : b;

Correct Answer: B. x = (a > b) ? a : b;

EXPLANATION

The ternary operator syntax is: condition ? value_if_true : value_if_false. Option B is the only correctly formatted statement.

Test

Q.67 Medium C Programming

What will be printed by: int x = 5; printf("%d", ++x + x++);?

A 11

B 12

C 13

D 14

Correct Answer: B. 12

EXPLANATION

# Understanding Pre-increment and Post-increment Operators in C

The key to solving this problem is understanding the difference between pre-increment (++x) and post-increment (x++) operators and their evaluation order.

Step 1: Evaluate Pre-increment (++x)

The pre-increment operator increases the variable first, then uses the updated value in the expression.

\text{++x means: } x = x + 1 \text{ first, then use the new value}

When ++x is evaluated, x changes from 5 to 6, and the expression uses 6.

Step 2: Evaluate Post-increment (x++) and Addition

The post-increment operator uses the current value in the expression first, then increments the variable afterward.

\text{Expression becomes: } 6 + 6 \text{ (where first 6 is from ++x, second 6 is current value of x before x++ takes effect)}

After the entire expression is evaluated, x++ increments x from 6 to 7, but this happens after the addition is complete.

Step 3: Calculate Final Result

\[6 + 6 = 12\]

The answer is (B) 12

Test

Q.68 Medium C Programming

What is the correct syntax to pass a 2D array to a function in C?

A func(int arr[][])

B func(int arr[rows][cols])

C func(int arr[][cols])

D func(int **arr)

Correct Answer: C. func(int arr[][cols])

EXPLANATION

When passing a 2D array to a function, the number of columns must be specified, but the number of rows is optional. Option C is the standard correct syntax.

Test

Q.69 Medium C Programming

What is the output of the expression: 10 / 3 * 3 in C?

A 10

B 9

C 3.33

D Cannot be determined

Correct Answer: B. 9

EXPLANATION

Division and multiplication have the same precedence and are evaluated left-to-right. Step 1: 10 / 3 = 3 (integer division). Step 2: 3 * 3 = 9. Therefore, the result is 9.

Test

Q.70 Medium C Programming

Which of the following is a correct way to initialize a pointer to NULL?

A int *ptr = 0;

B int *ptr = NULL;

C int *ptr = (void*)0;

D All of the above

Correct Answer: D. All of the above

EXPLANATION

All three methods are correct ways to initialize a pointer to NULL. 0, NULL, and (void*)0 all represent a null pointer. NULL is typically a macro defined as 0 or ((void*)0) in the standard library.

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