C Programming - MCQ Practice Questions

In a program that processes binary files with variable-length records, what could cause fread() to return fewer items than requested without reaching EOF?

Which header file is required for dynamic memory allocation functions?

What does calloc() do differently from malloc()?

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

Which function is used to free dynamically allocated memory?

What is a memory leak in C?

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

What is the purpose of realloc() function?

Which of the following is correct for dynamic array allocation?

What is double free error?

Analyze this code: char *str = malloc(5); strcpy(str, "Hello"); How many bytes should malloc allocate for safety?

What is the output? int *p = malloc(sizeof(int) * 3); p[0] = 1; p[1] = 2; p[2] = 3; printf("%d", *(p+2));

What will happen if malloc() fails and returns NULL but code doesn't check?

Which statement about dynamic memory is TRUE?

What is the issue in this code? void func() { int *p = malloc(sizeof(int)); *p = 5; } int main() { func(); // p is not accessible here return 0; }

What is the correct way to allocate memory for 2D dynamic array (3x4)?

What does this realloc() call do? int *p = malloc(5 * sizeof(int)); p = realloc(p, 10 * sizeof(int));

How much memory is allocated by malloc(sizeof(int) * 10) on a 32-bit system where sizeof(int) = 4?

Which header file must be included to use malloc(), calloc(), and free() functions?

What is the key difference between malloc() and calloc()?