Dynamic Memory Allocation

Local variables are stored in an area called ___________
1. Heap
2. Permanent storage area
3. Free memory
4. Stack
The size of both stack and heap remains the same during run time.
1. true
2. false
Choose the statement which is incorrect with respect to dynamic memory allocation
1. Memory is allocated in a less structured area of memory, known as heap
2. Used for unpredictable memory requirements
3. Execution of the program is faster than that of static memory allocation
4. Allocated memory can be changed during the run time of the program based on the requirement of the program
Which of the following header files must necessarily be included to use dynamic memory allocation functions?
1. stdlib.h
2. stdio.h
3. memory.h
4. dos.h
What will be the output of the following C code if the input entered as first and second number is 5 and 6 respectively?
#include<stdio.h>
#include<stdlib.h>
main()
{
int *p;
p=(int*)calloc(3*sizeof(int));
printf("Enter first number\n");
scanf("%d",p);
printf("Enter second number\n");
scanf("%d",p+2);
printf("%d%d",*p,*(p+2));
free(p);
}
1. 56
2. Address of the locations where the two numbers are stored
3. 57
4. error
In the function malloc(), each byte of allocated space is initialized to zero
1. true
2. false
Which of the following functions allocates multiple blocks of memory, each block of the same size?
1. malloc()
2. realloc()
3. calloc()
4. free()
A condition where in memory is reserved dynamically but not accessible to any of the programs is called ___________
1. Memory leak
2. Dangling pointer
3. Frozen memory
4. Pointer leak
What will happens if the statement free(a) is removed in the following C code?

#include<stdio.h>
#include<stdlib.h>
main()
{
int *a;
a=(int*)malloc(sizeof(int));
*a=100;
printf("*a%d",*a);
free(a);
a=(int*)malloc(sizeof(int));
*a=200;
printf("a%p",a);
*a=200;
printf("a%d",*a);
}
1. Error
2. Memory leak
3. Dangling pointer arises
4. 200 is printed as output
The incorrect statement with respect to dangling pointers is ___________
1. Pointer pointing to non-existent memory location is called dangling pointer
2. When a dynamically allocated pointer references the original memory after it has been freed, a dangling pointer arises
3. If memory leak occurs, it is mandatory that a dangling pointer arises
4. Dangling pointer may result in segmentation faults and potential security risks
What will be the output of the following C code?

#include<stdio.h>
#include<stdlib.h>
void main()
{
char *p = calloc(100, 1);
p = "welcome";
printf("%s\n", p);
}error
1. error
2. welcome
3. memory location stored by the pointer
4. junk value
In the function realloc(), if the new size of the memory block is larger than the old size, then the added memory ___________is initialized to junk values
1. is initialized to junk values
2. is initialized to zero
3. results in an error
4. is not initialized
The free() function frees the memory state pointed to by a pointer and returns ___________
1. the same pointer
2. the memory address
3. no value
4. an integer value
The following C code is an example of __________

#include<stdio.h>
#include<stdlib.h>
#include
main()
{
char *p,*q;
p=(char*)malloc(3*sizeof(char));
q=p;
strcpy(p,"hello");
printf("p=%s",p);
printf("q=%s",q);
free(q);
q=NULL;
gets(p);
gets(q);
printf("%s",p);
printf(“%s”,q);
}
1. Memory leak
2. Dangling pointer
3. Static memory allocation
4. Linked list
What will be the output of the following C code if it is executed on a 32 bit processor?
#include<stdio.h>
#include<stdlib.h>
int main()
{
int *p;
p = (int *)malloc(20);
printf("%d\n", sizeof(p));
free(p);
return 0;
}
1. 2
2. 4
3. 8
4. junk value
The number of arguments taken as input which allocating memory dynamically using malloc() is ___________
1. 0
2. 1
3. 2
4. 3
Suppose we have a one dimensional array, named ‘x’, which contains 10 integers. Which of the following is the correct way to allocate memory dynamically to the array ‘x’ using malloc()?
1. x=(int*)malloc(10);
2. x=(int*)malloc(10,sizeof(int));
3. x=malloc(int 10,sizeof(int));
4. x=(int*)malloc(10*sizeof(int));
What will be the error (if any) in the following C code?

#include<stdio.h>
#include<stdlib.h>
#include
int main()
{
char *p;
*p = (char)calloc(10);
strcpy(p, "HELLO");
printf("%s", p);
free(p);
return 0;
}
1. No error
2. Error in the statement: strcpy(p,”HELLO”);
3. Error in the statement: *p=(char)calloc(10);
4. Error in the statement: free(p);
If malloc() and calloc() are not type casted, the default return type is ________
1. void*
2. void**
3. int*
4. char*
Pick out the correct statement with respect to the heap.
1. Local variables are stored on the heap
2. Static variables are stored on the heap
3. Heap is the data structure which is used to implement recursive function calls
4. Everything on the heap is anonymous
What will be the output of the following C code? (Given that the size of array is 4 and new size of array is 5)

#include<stdio.h>
#include<stdlib.h>
main()
{
int *p,i,a,b;
printf("Enter size of array");
scanf("%d",&a);
p=(int*)malloc(a*sizeof(int));
for(i=0;i<a;i++)
printf("%d\n",i);
printf("Enter new size of array");
scanf("%d",&b);
realloc(p,b);
for(i=0;i<b;i++)
printf("%d\n",i);
free(p);
}
1. 1234
  12345
2. Error
3. 0123
  01234
4. 0123
  12345
When the pointer is NULL, then the function realloc is equivalent to the function __________
1. malloc
2. calloc
3. free
4. alloc
Garbage collector frees the programmer from worrying about _________
1. Dangling pointers
2. Creating new objects
3. Memory leak
4. Segmentation errors
If the space in memory allocated by malloc is not sufficient, then an allocation fails and returns ___________
1. NULL pointer
2. Zero
3. Garbage value
4. The number of bytes available

Dynamic Memory Allocation

Quiz