Common Coding Interview Questions For .NET Interview

This article explains commonly asked coding example questions in technical rounds for .NET interviews. Here, I have given some examples with the code to help the developers prepare for a technical interview. It looks simple but during the interview, it will be difficult to explain or write on paper.

 

I have attached the source code with this article for all the below examples.

 

Common programs to build that interviewers ask during .NET interviews

static void Main(string[] args)
{
            //Write Program to find fibonacci series for given number
            for (int i = 0; i < 10; i++)
            {
                Console.Write("{0} ", FibbonacciSeries(i));
            }
            Console.WriteLine(Environment.NewLine);

            Console.Write("Fibbonacci Series of {0} is : {1} ", 10, FibbonacciSeries1(10));

            Console.WriteLine(Environment.NewLine);

            //Write Program to calculate factorial value for given number
            Console.WriteLine("The Factorial of {0} is: {1} \n", 6, Factorial(6));

            //Write Program to find duplicate in String
            FindDuplicateCharacterInString("CSharpCorner");

            Console.WriteLine(Environment.NewLine);
            //Write Program to find duplicate in string array
            FindDuplicateInstringArray();

            Console.WriteLine(Environment.NewLine);
            //Write Program to Remove duplicate in string
            RemoveDuplicate("CSharpCorner");

            Console.WriteLine(Environment.NewLine);
            //Write Program to find number of character in string
            FindNumberofCharaterinString();

            Console.WriteLine(Environment.NewLine);
            //Write Program to find number of words in string
            ReverseStringWords("Jignesh Kumar");

            Console.WriteLine(Environment.NewLine);
            //Write Program to find consicutive character in string
            char[] charArray = { 'A', 'B', 'B', 'C', 'D', 'D', 'E', 'F', 'F' };
            FindConsicutiveCharacter(charArray);

            Console.WriteLine(Environment.NewLine);
            //Write Program to check string is palindrome or not
            string[] strArray = { "WOW", "NOON", "ABBA", "ANNA", "BOB", "Jimmy", "Peter" };

            foreach (var item in strArray)
            {
                Console.WriteLine(" {0} Is palindrome {1}", item, IsStringPalindrome(item));
            }

            Console.WriteLine(Environment.NewLine);
            //Write program to check number is palindrome or not
            int number = 121;
            Console.WriteLine("{0} is Palindrome number {1} ", number, IsNumberPalindrome(number));

            Console.WriteLine(Environment.NewLine);
            //Write program to check number is palindrome or not
            number = 127;
            Console.WriteLine("{0} is prime number {1} ", number, IsNumberPrime(number));
            number = 128;
            Console.WriteLine("{0} is prime number {1} ", number, IsNumberPrime(number));
            Console.ReadLine();
}

Write a program for printing a fibonacci series for a given number

private static int FibbonacciSeries(int number)
{
           int firstValue = 0;
           int secondValue = 1;
           int result = 0;
           if (number == 0)
               return 0;
           if (number == 1)
               return 1;
           for (int i = 2; i <= number; i++)
           {
               result = firstValue + secondValue;
               firstValue = secondValue;
               secondValue = result;
           }
           return result;
 }

public static string FibbonacciSeries1(int n)
{
           int a = 0, b = 1, c;
           StringBuilder sb = new StringBuilder();
           for (int i = 1; i < n; i++)
           {
               sb.Append(a.ToString() + ",");
               c = a + b;
               a = b;
               b = c;
           }
           return sb.ToString().Remove(sb.Length - 1); ;
}

Write a program to calculate factorial value for a given number

private static int Factorial(int number)
{
           int fact = 1;
           if (number == 0)
               return 0;
           if (number == 1)
               return 1;

           for (int i = 1; i <= number; i++)
           {
               fact = fact * i;
           }
           return fact;
}

Write a program to find duplicate in String

private static void FindDuplicateCharacterInString(string inPutString)
{

            if (string.IsNullOrEmpty(inPutString))
            {
                Console.WriteLine("Please enter valid Input");
            }
            else
            {
                var list = new List<char>();
                string result = string.Empty;

                foreach (char item in inPutString)
                {
                    if (list.Contains(item))
                    {
                        if (!result.Contains(item))
                            result += item;
                    }
                    else
                    {
                        list.Add(item);
                    }
                }
                Console.WriteLine("Duplicate Found : {0} ", result);
            }
}

Write a program to find duplicate in a string array

public static void FindDuplicateInstringArray()
{
            string[] strArray = { "Sunday", "Monday", "Tuesday", "Wednesday", "Sunday", "Monday" };
            List<string> lstString = new List<string>();
            StringBuilder sb = new StringBuilder();

            foreach (var str in strArray)
            {
                if (lstString.Contains(str))
                {
                    sb.Append(" " + str);

                }
                else
                {
                    lstString.Add(str);
                }
            }
            Console.WriteLine("Duplicate Found : {0}", sb.ToString());
}

Write a program to remove duplicate in string:

public static void RemoveDuplicate(string inputString)
{
            var list = new List<char>();

            foreach (var item in inputString)
            {
                if (!list.Contains(item))
                {
                    list.Add(item);
                }
            }

      Console.WriteLine("Orignal String {0}, After duplicate removed {1}", inputString, new string(list.ToArray()));
}

Write a program to find a number of character in a string

public static void FindNumberofCharaterinString()
{
            string StringToCount = "DotNetDeveloper";
            var result = FindOccuranceofCharacterInString(StringToCount);

            Console.WriteLine("Number of occurrences of a character in given string");
            foreach (var count in result)
            {
                Console.WriteLine(" {0} - {1} ", count.Key, count.Value);
            }
}

public static SortedDictionary<char, int> FindOccuranceofCharacterInString(string str)
{
 SortedDictionary<char, int> count = new SortedDictionary<char, int>();

            foreach (var chr in str)
            {
                if (!(count.ContainsKey(chr)))
                {
                    count.Add(chr, 1);
                }
                else
                {
                    count[chr]++;
                }
            }

    return count;
}

Write a program to find a number of words in a string

public static void ReverseStringWords(string inputString)
{
            string[] seprator = { " " };
            string[] words = inputString.Split(seprator, StringSplitOptions.RemoveEmptyEntries);
            string result = string.Empty;
            for (int i = words.Length - 1; i >= 0; i--)
            {
                result += words[i].ToString();
            }
     Console.WriteLine("Reverse words in string {0}", result);
}

Write a program to find the consecutive characters in a string

public static void FindConsicutiveCharacter(char[] characterArray)
{
           int len = characterArray.Length - 1;
           List<char> result = new List<char>();
           for (int i = 0; i < len; i++)
           {
               for (int j = i + 1; j <= len; j++)
               {
                   if (characterArray[i] == characterArray[j])
                   {
                       if (!result.Contains(characterArray[i]))
                           result.Add(characterArray[i]);
                       continue;
                   }
                   else
                   {
                       break;
                   }
               }
           }

           Console.WriteLine("Consicutive Character found {0} ", new string(result.ToArray()));
}

Write a program to check if a string/number is a palindrome or not

public static bool IsStringPalindrome(string inputString)
{
            int minIdex = 0;
            int maxIdex = inputString.Length - 1;
            while (true)
            {
                if (minIdex > maxIdex)
                {
                    return true;
                }
                char charfromLeft = inputString[minIdex];
                char charfromRight = inputString[maxIdex];
                if (charfromLeft != charfromRight)
                {
                    return false;
                }
                minIdex++;
                maxIdex--;
            }
}
public static bool IsNumberPalindrome(int number)
{
            int reminder, sum = 0;
            int tempNumber;
            tempNumber = number;
            bool IsPalindrome = false;
            while (number > 0)
            {
                reminder = number % 10;
                number = number / 10;
                sum = sum * 10 + reminder;
                if (tempNumber == sum)
                {
                    IsPalindrome = true;
                }
            }
            return IsPalindrome;
}

Write a program to check if a number is prime or not

public static bool IsNumberPrime(int number)
{
            int i;
            for (i = 2; i <= number - 1; i++)
            {
                if (number % i == 0)
                {
                    return false;
                }
            }
            if (i == number)
            {
                return true;
            }
            return false;
}

 

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