IT Trainer Questions

A data structure is a specialized format for organizing and storing data. General data structure types include the array, the file, the record, the table, the tree, and so on. Any data structure is designed to organize data to suit a specific purpose so that it can be accessed and worked with in appropriate ways.

Linear data structure: A linear data structure traverses the data elements sequentially, in which only one data element can directly be reached.

Ex: Arrays, Linked Lists, Stack, Queue, Any type of List all are linear.

Trees like Binary Tree, B Tree or B+ Tree are examples of non linear data structure.

ArrayList and LinkedList both implements List interface and maintains insertion order. Both are non synchronized classes.

But there are many differences between ArrayList and LinkedList classes that are given below.

ArrayList    V/s     LinkedList ::

1) ArrayList internally uses dynamic array to store the elements.

                   Whereas

LinkedList internally uses doubly linked list to store the elements.

2) Manipulation with ArrayList is slow because it internally uses array. If any element is removed from the array, all the bits are shifted in memory.

                   Whereas

Manipulation with LinkedList is faster than ArrayList because it uses doubly linked list so no bit shifting is required in memory.

3) ArrayList class can act as a list only because it implements List only.

                   Whereas

LinkedList class can act as a list and queue both because it implements List and Deque interfaces.

4) ArrayList is better for storing and accessing data.

                   Whereas

LinkedList is better for manipulating data.

Function: A Function is a block of statement which perform some operation.

Declaring the function before using the function in program is known as implicit declaration of the function.

For Example::

int bar(void); // function (forward) declaration

int main(void) {

bar(); // bar was declared, the compiler has all the info

return foo(123); // foo not yet known; impl. decl. warning

}

// not previously declared function definition

int foo(int a) {

return a;

} 

// previously declared function definition

int bar() {

return 321;

}

Compound word means when two or more words join together to make a single word that gives a new meaning.

Here in the options, Self-evident is the compound word.

In a SQL Database, a 'correlated subquery' is a kind of sub query yet connected subquery is dependent on another query for a value that is returned. In case of execution, the sub query is executed first and afterwards the correlated query will be executed.

The product of a number and its reciprocal is always equals to 1.

For Example : Let the number be 4.

Now, its reciprocal is 1/4

Hence, required product = 4 x 1/4 = 1.

Now, take the number as -15.

Then its reciprocal is -1/15

Required product = -15 x -1/15 = 1.

Hence, the product of a number and its reciprocal is 1.

Photography is a word derived from Greek words Photo means light and graphe means drawing.'Hence it literally means light drawing.

The given expression can be simplified as

6 ÷ 2 (1 + 2)

The expression can be simplified further by the order of operations, using BODMAS rule.

First evaluate Parentheses/Brackets, then evaluate Exponents/Orders, then evaluate Multiplication-Division, and finally evaluate Addition-Subtraction.

Now, the expression becomes 6 ÷ 2 (3)

According to the order of operations, division and multiplication have the same precedence, so the correct order is to evaluate from left to right. First take 6 and divide it by 2, and then multiply by 3.

6 ÷ 2 × 3

= 3 × 3

= 9

But not  6÷2×3 = 6 ÷ 6 = 1

Hence, 6 ÷ 2 (1 + 2) = 9.