What will be printed by: printf("%s", "Hello\0World");?

The correct answer is B: Hello. \0 is the null terminator which marks the end of a string. %s stops printing at the first null character.

What is the purpose of the main() function in C?

The correct answer is C: Entry point of program execution. The main() function is the entry point where program execution begins. Every C program must have a main() function.

Which of the following is a memory leak?

The correct answer is A: int *p = malloc(100); p = malloc(50);. In option A, the first malloc(100) block becomes inaccessible after p is reassigned, but it's not freed, causing a memory leak. The original 100 bytes are lost.

Which of the following variable declarations will occupy the LEAST memory?

The correct answer is C: char z;. char data type typically occupies 1 byte, which is the minimum. int is 4 bytes, float is 4 bytes, and double is 8 bytes on most systems.

Which memory allocation technique provides better locality of reference for accessing array elements?

The correct answer is B: Single malloc for contiguous array. Contiguous allocation places array elements next to each other in memory, improving cache hits and CPU performance through spatial locality.

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C Programming
Dynamic Memory

C language from basics to advanced placement prep

53 Q 10 Topics Take Mock Test

Difficulty: All Easy Medium Hard 51–53 of 53

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.51 Medium Dynamic Memory

What happens when you try to access memory after calling free()?

A Automatic reallocation

B Use-after-free error (undefined behavior)

C Returns NULL

D Program terminates gracefully

Correct Answer: B. Use-after-free error (undefined behavior)

EXPLANATION

Accessing freed memory results in undefined behavior and is a critical bug. The memory may be reallocated for other purposes.

Test

Q.52 Medium Dynamic Memory

What is a memory leak in C?

A Accessing freed memory

B Allocated memory that is never freed

C Memory overflow

D Stack overflow

Correct Answer: B. Allocated memory that is never freed

EXPLANATION

A memory leak occurs when allocated memory is not freed, consuming system resources without releasing them back.

Test

Q.53 Medium Dynamic Memory

What will be the output of the following code?
int *ptr = malloc(sizeof(int));
if(ptr == NULL) printf("Failed");
else printf("Success");

A Failed

B Success

C Compilation Error

D Runtime Error

Correct Answer: B. Success

EXPLANATION

In typical scenarios, malloc() successfully allocates memory and returns non-NULL pointer, printing 'Success'. NULL check is good practice for error handling.

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Dynamic Memory