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Interview Questions and Answers on malloc() & free() in C : (10)

Question: 1

Point out the wrong statement about malloc

(A) Allocated memory has undefined value
(B) It returns pointer to the allocated space
(C) Pointer is NULL if memory is not allcoated
(D) It doesn't lead to memory leak if memory is not de allocated

Compiler
Level: Beginner Category: malloc_free
[Posted by: Admin | Chicago, USA]

Question: 2

In C programming it is not mandatory to typecast pointer return by malloc() function

(A) True
(B) False

Compiler
Level: Beginner Category: malloc_free
[Posted by: Admin | Chicago, USA]

Question: 3

Find output of below C program

#include <stdio.h>

int main()
{
   char *_ptr;
   *_ptr = malloc(10);
   *_ptr = 999;
   printf("%d",*_ptr);
    return 0;
}

(A) 999
(B) 10
(C) 0
(D) Segmentation fault

Compiler
Level: Expert Category: malloc_free
[Posted by: Admin | Chicago, USA]

Question: 4

#include <stdio.h>

int main()
{
   char *_ptr = malloc(100);
   strcpy(_ptr, "cppbuzz");
   memset(_ptr, NULL, sizeof(_ptr));
   if(*_ptr == NULL)
   printf("NULL");
   else
   printf("%s",_ptr);
return 0;
}

(A) NULL
(B) cppbuzz
(C) Nothing is printed
(D) Typecasting Error

Compiler
Level: Expert Category: malloc_free
[Posted by: Admin | Chicago, USA]

Question: 5

#include "stdio.h"

int main()
{
   char *_ptr = malloc(100);
   if(_ptr!=NULL)
   free(_ptr);
   
   free(_ptr);
return 0;
}

(A) Program runs smoothly
(B) Compilation Error
(C) Runtime Error- Program crashes

Compiler
Level: Expert Category: malloc_free
[Posted by: Admin | Chicago, USA]

Question: 6

Freeing memory using free() does not set the pointer to NULL

(A) True
(B) False

Compiler
Level: Practionar Category: malloc_free
[Posted by: Admin | Chicago, USA]

Question: 7

#include <stdio.h>

int main()
{
   char *_ptr = malloc(100);
   if(_ptr!=NULL)
   free(_ptr);
  _ptr=NULL;
   free(_ptr);
   return 0;
}

(A) Program runs smoothly & nothing is printed
(B) Runtime Error : Crash
(C) Compilation Error
(D) None of these

Compiler
Level: Practionar Category: malloc_free
[Posted by: Admin | Chicago, USA]

Question: 8

#include <stdio.h>

int main()
{
	char *_ptr = malloc(1);
	_ptr = malloc(1);
	free(_ptr);
	return 0;
}

(A) Program runs smoothly
(B) Compilation Error
(C) Program runs smoothly but has memory leak
(D) Runtime Error : Crash

Compiler
Level: Practionar Category: malloc_free
[Posted by: Admin | Chicago, USA]

Question: 9

How malloc() behaves if we passes 0 in argument?

#include <stdio.h>

int main()
{
char *_ptr = malloc(0);
free(_ptr);
return 0;
}

(A) Compilation Error
(B) Runtime Error: Crash
(C) Program runs smoothly but has memory leak
(D) Program runs smoothly & nothing is printed

Compiler
Level: Practionar Category: malloc_free
[Posted by: Admin | Chicago, USA]

Question: 10

#include <stdio.h>

int main()
{
   char * _ptr = NULL; 
   _ptr = malloc(0);
   if(_ptr==NULL) printf("_ptr is NULL");
   else printf("_ptr not NULL");
   printf(" %p ", _ptr);
   *_ptr = '@';
   printf(" %c ", *_ptr);
   free(_ptr);
   return 0;
}

(A) _ptr is NULL 0x21f3010 @
(B) _ptr not NULL 0x21f3010 @
(C) Runtime Error: Segmentation Fault
(D) _ptr not NULL 0x21f3010

Compiler
Level: Expert Category: malloc_free
[Posted by: Admin | Chicago, USA]

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Interview Questions and Answers on malloc() & free() in C : (10)

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