What does the following nested if-else produce? int a = 10, b = 20; if (a > b) if (b > 0) printf("X"); else printf("Y");

The correct answer is B: Y. The else clause pairs with the inner if. Since a > b is false, the else block executes printing 'Y'.

What is the primary use of const pointer (int * const p)?

The correct answer is B: Prevent modification of the pointer itself. int * const p is a constant pointer - the pointer address cannot be changed, but the value it points to can be modified.

In the context of function pointers, what does the restrict keyword do?

The correct answer is B: Tells the compiler that the pointer is the only way to access the data. The restrict keyword informs the compiler that the pointer is the sole means of accessing the data it points to, allowing for optimization. It's a hint for compiler optimization.

What will happen? char arr[5] = "Hello"; printf("%d", strlen(arr));

The correct answer is C: Compilation error. Array is too small. "Hello" needs 6 bytes including null terminator, but only 5 are allocated. This causes buffer overflow.

What does the following macro do? #define CONCATENATE(a,b) a##b

The correct answer is B: Uses token pasting to combine two identifiers into one at preprocessing stage. The ## operator (token pasting operator) concatenates two tokens into a single token during preprocessing. For example, CONCATENATE(var,1) becomes var1.

Home

Home › Subjects › C Programming › Arrays & Strings

C Programming
Arrays & Strings

C language from basics to advanced placement prep

49 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 21–30 of 49

Topics in C Programming

All Basics & Syntax 86 Data Types & Variables 97 Control Flow 100 Functions 99 Arrays & Strings 100 Pointers 99 Structures & Unions 100 File Handling 100 Dynamic Memory 98 Preprocessor 99

Q.21 Medium Arrays & Strings

What is the output of the following code?
char str[] = "GATE";
printf("%d", sizeof(str));

A 4

B 5

C 8

D Compilation error

Correct Answer: B. 5

EXPLANATION

sizeof(str) returns 5 because the array includes 4 characters plus 1 null terminator.

Test

Q.22 Medium Arrays & Strings

Which of the following correctly reverses a string in-place?

A strrev(str);

B reverse(str);

C str_reverse(str);

D reversestr(str);

Correct Answer: A. strrev(str);

EXPLANATION

strrev() is a non-standard but commonly used function (available in string.h in some compilers) that reverses a string in-place.

Test

Q.23 Medium Arrays & Strings

What happens when you try to modify a string literal in C?
char *str = "Hello";
str[0] = 'J';

A String is successfully modified to 'Jello'

B Undefined behavior or runtime error

C Compilation error

D String remains 'Hello'

Correct Answer: B. Undefined behavior or runtime error

EXPLANATION

String literals are stored in read-only memory. Attempting to modify them causes undefined behavior or segmentation fault.

Test

Q.24 Medium Arrays & Strings

What is the correct way to declare a pointer to a character array?

A char *ptr[];

B char (*ptr)[];

C *char ptr[];

D char **ptr;

Correct Answer: B. char (*ptr)[];

EXPLANATION

char (*ptr)[] declares ptr as a pointer to a character array. The parentheses are crucial for correct precedence.

Test

Q.25 Medium Arrays & Strings

What does strtok(str, delim) return on each call until the string ends?

A The entire remaining string

B A pointer to the next token

C The delimiter character

D The length of the token

Correct Answer: B. A pointer to the next token

EXPLANATION

strtok() returns a pointer to the next token separated by the delimiter. Returns NULL when no more tokens exist.

Test

Q.26 Medium Arrays & Strings

Consider: char str[10]; strcpy(str, "Hello"); What is the state of memory after this?

A str[5] contains '\0', str[6] is uninitialized

B All elements from str[0] to str[9] contain characters

C str[0] to str[4] have 'H','e','l','l','o', str[5] has '\0'

D Runtime error occurs

Correct Answer: C. str[0] to str[4] have 'H','e','l','l','o', str[5] has '\0'

EXPLANATION

strcpy copies "Hello" and adds null terminator at position 5. Positions 6-9 remain uninitialized.

Test

Q.27 Medium Arrays & Strings

What does the following code do?
char str[] = "HELLO";
for(int i = 0; str[i]; i++) str[i] = str[i] + 32;

A Converts uppercase to lowercase

B Converts lowercase to uppercase

C Shifts ASCII values by 32

D Causes compilation error

Correct Answer: A. Converts uppercase to lowercase

EXPLANATION

Adding 32 to uppercase ASCII values converts them to lowercase (A=65, a=97, difference=32).

Test

Q.28 Medium Arrays & Strings

What is the correct syntax to concatenate two strings safely in modern C?

A strcat(dest, src)

B strncat(dest, src, n)

C sprintf(dest, "%s%s", dest, src)

D Both B and C are safer options

Correct Answer: D. Both B and C are safer options

EXPLANATION

strcat() is unsafe due to buffer overflow risk. strncat() and sprintf() provide bounds checking.

Test

Q.29 Medium Arrays & Strings

Which of the following will correctly compare two strings?

A if (str1 == str2)

B if (strcmp(str1, str2) == 0)

C Both A and B

D Neither A nor B

Correct Answer: B. if (strcmp(str1, str2) == 0)

EXPLANATION

A compares pointers, not string content. strcmp() compares actual string values character by character.

Test

Q.30 Medium Arrays & Strings

Consider the code: int *p; int arr[5] = {10, 20, 30, 40, 50}; p = arr; What is *(p+2)?

A 20

B 30

C 40

D 50

Correct Answer: B. 30

EXPLANATION

p points to arr[0]. p+2 points to arr[2], which contains 30.

Test

1 2 3 4 5

All Subjects & Topics

Govt. Exams

Entrance Exams

Teacher Exams

Subjects

Quick Links

C Programming Arrays & Strings

C Programming
Arrays & Strings