Array and LinkedList MCQs

Answer: Option 4

Concept: 

Full Binary Tree: 

A full binary tree is a binary tree in which each node has exactly two or 0 children.

Complete Binary Tree:

A complete binary tree is a binary tree in which

1. except last level tree is completely filled.
2. The last level is filled from left to right.

Perfect Binary Tree: 

A perfect binary tree is a binary tree in which

1. all interior node or internal nodes has 2 children.
2. all leaves are at the same level.

Balanced Binary Tree: 

A Balanced Binary tree is a binary tree in which at any node height of the left sub tree and right sub tree do not differ by more than 1.

In an "m-ary" tree. the number of total nodes (N) is given by

N=mi + 1  ----(1)

Where,

i: Number of internal nodes

Also, in a tree, N=i + L   ----(2)

Where,

L=number of leaf nodes

Here m=2

From equation (1) and equation (2);

N = 2i + 1

2i + 1 = i + L

L = i + 1

The number of leaves are 1 plus the number of internal nodes in binary tree.

Here, given L=n, substitute above and we will get,

i = L - 1

Concept –

Option_1: A valid declaration in C.

char *str is a single value which is a pointer to a character. When used as a string in C, it is implied that subsequent characters of the string are stored in subsequent memory addresses, until the end of the string which is marked with a NULL.

Option_2: A valid declaration in C.

Char str[20] is an array of maximum 20 characters. It is similar to char *str except that there is no requirement that the last character in the array be null.

Option_3 – A valid declaration in C.

char str[40] is an array of maximum 40 characters. It is similar to char *str except that there is no requirement that the last character in the array be null.

Option_4: Not a valid declaration in C.

Answer Option 1

Concept: 

Explanation: 

Option 1: The linked list is slower in add and remove, but faster in get.

This is the only option that is incorrect since Linked list adding and removing the given element is faster as compared to an array but finding a particular indexed element we might have to traverse to entire list but in case of array random access possible.

Answer: Option 4

Explanation: 

Consider the following example 

#include <stdio.h>
int main()
{
       int arr[10] = {1, 2, 3, 4, 5, 6, 7};

       arr++;
       return 0;
}

Here arr++; mean that

arr = arr + 1 ;

which is wrong we can not change the base address of an array and it will generate an error.
another way to do that is by using pointers.

#include <stdio.h>
int main()
{
       int arr[10] = {1, 2, 3, 4, 5, 6, 7};

       int *p = arr;

       p++;
       return 0;
}

Here int *p = arr; new pointer variable will be created which will start pointing to the first element of the array.

and p++; will cause the pointer to start pointing to the next element of the array.

Answer: Option 3

Explanation: 

- arr denote the Base address of the array.

- &arr will not work the same way as some of you think.

printf("%ld\n",arr+1);

- In the First printf ; arr +1 , addition of 1 resulted in an address increment of 1 int data size hence 2000 + 4 = 2004 will be printed

printf("%ld",(&arr + 1));
- &arr will return a pointer to the whole array of 10 int, addition of 1 resulted in an address with an increment of 4 x 10 = 40 and hence 2040 will be printed in next line.

Hence Option 3 is the correct answer.

Declaration syntax: For structure in C and C++

struct tag_name

{

Datatype  variable_name;

struct tag_name *pointer_variable;

};

Option 2:

struct node

{

int data;

struct node*link;

}

Circular linked list:
In singly linked lists and doubly linked lists, the end of lists is indicated with a NULL value. But circular linked lists do not have ends. In circular linked lists, each node has a successor, and the last node points to the first node instead of NULL.

Example

Let x be a variable pointer and head.

Head is the pointer of the circular linked list.

Now to insert a new record (node) y, we have to loop through the linked list from the head to the last node like this pseudocode below.

x=head

while(x->next!=head)

{

   x=x->next;

}

After finishing the loop x is now the last node and we will append the list. y is the next node of x Then the next of y will have to point to the head since the linked list is circular. The pseudocode for this task is below.

x->next=y;

y->next=head; 

So There needs modification of two pointers. 

So the correct answer is Option 3

Concept:

By the definition of a Binary Search Tree (BST), the value of left child node <= root node < right child node or left child node < root node <= right child node.

In inorder traversal, we visit left node first, then root node and then right node. Hence, the inorder traversal always returns values in ascending order if it is run on a Binary Search Tree.

Explanation:

Binary Search Tree:

Apply Inorder Traversal

This will print 1-2-3.

This will print 1-2-3-4 and then 1-2-3-4-5-6-7

Output of Traversal: 1-2-3-4-5-6-7 (sorted order)

Important Points:

There are usually three methods of traversing a BST - Preorder, Postorder, Inorder.

• In preorder, we visit nodes in the order of Root -> Left -> Right
• In postorder, we visit nodes in the order of Left -> Right -> Root
• In inorder, we visit nodes in the order of Left -> Root -> Right

While loop:

In the while loop, the expression is evaluated.  If it is non-zero, the statement is executed and the expression is re-evaluated. This cycle continues until expression becomes zero, at which point execution resumes after the statement. 

For loop:

In the case of for loop, expr₁ is an assignment or function call, expr₂ is a relational expression while expr₃ is also an assignment or function call. The for loop basically assigns the value to a variable using expr₁, expr₂ is used to evaluate the expression, and expr₃ is used to modify the value of expr₂ so that the terminating condition is reached.

This functionality can be achieved using the while statement as listed in option 3.