NEC Technologies Interview Questions

Coding round questions

  • Display all numbers between 32-62 which ends with 5.
  • Write a program that accepts a decimal number and outputs the binary representation of that number.
  • Given ASCII values, output the string.
  • You are given an m x n 2D matrix. Rotate the image by 90 degrees (anti-clockwise).
  • Write a program to convert infix to postfix.
  • Write a program to print transpose of a given matrix.
  • Given a 2D array, find the maximum sum subarray in it.
  • Given a binary search tree, write a function kthSmallest to find the kth smallest element in it.
  • Given a text file, I want the words to be scanned from it, along with their occurrences, sort them in descending order, & display the top 10 words.
  • Find the second largest number.
  • Find whether two strings are anagram of each other.
  • Find missing number unsorted contiguous array.
  • Find Number of common Guests in all parties if user give the input in the following format. The guests list for parties is in one line separated by Comma(,).
     Input: 122,444,2223,122,1111,122,2233,123,333,333,444,   1111,122 Output:   2233:1   2223:1   333:2   444:2   1111:2   122:4   123:1

Technical Interview Questions 
Data Structures and Algorithms

  • Write a recursive function to print reverse of a Linked List.
  • Write a program in C/C++ to sort an Array in O(n).
  • WAP to reverse a linked list.
  • Implement queue.
  • What are the advantages of doubly linked list.
  • Various types of Hashing-Linear, Quadratic and Mid-Square.
  • Decimal to Binary program using recursion.
  • Find the largest Number of Array using recursion.
  • WAP to sort a Linked List.
  • Program for converting Little to Big Endian.
  • Find the center element of a linked list?
  • Print left view of Binary Search Tree.
  • Implement circular linked list.
  • Write a program on pallindrome linked list and stack implementation using linked list.
  • Program to remove duplicates from linked list.
  • Program to detect if there is any loop in linked list.
  • Write program for maximum of 4 numbers in good readable, optimized code.


  • Database design using Normalization.
  • What are DBMS, RDBMS and ORDBMS ?
  • What is DDL, DML and DCL?
  • What is clustered indexing?
  • Transaction and normalisation.

Operating System

  • Define Semaphores, Fragmentation, Normalization?
  • Discuss about Deadlock, Cyclic wait.
  • Paging and segmentation.
  • What is thrashing?
  • What is the difference between mutex and binary semaphore?
  • Can you name some IPC(Inter-process communication) mechanism?


  • How to implement a class in C?
  • Difference between C and C++.
  • What is template ?
  • Elaborate upon the fact of inheritance in C structures.
  • How can you make the same variable accessible to two C programs ?
  • Define Synchronization, Desynchronization, Interim, Manipulation(Java).
  • Name the technologies to store Sequential Files.
  • Difference between exe and dll.
  • Discussion about Volatile(in C).
  • Difference between const, const pointer, const to pointer(in C).
  • What is virtual function in C++? What is pure virtual function?
  • What is dual core, cache m/m, throughput of processors.
  • Abstract class and Interface in Java.
  • What is difference between virtual and static class.
  • Differentiate between Call by value, call by address, call by refrence.
  • Implement operator overloading in C++?