Homework 02 - Methods

01_BiggerNumber.cs

using System;

/*
 * Write a method GetMax() with two parameters that returns the larger of two integers. 
 * Write a program that reads 2 integers from the console and prints the largest of them
 * using the method GetMax().
 */


class BiggerNumber
{
    private static int GetMax(int first, int second)
    {
        return first > second ? first : second;
    }

    static void Main()
    {
        int firstNumber = int.Parse(Console.ReadLine());
        int secondNumber = int.Parse(Console.ReadLine());

        int max = GetMax(firstNumber, secondNumber);
        Console.WriteLine(max);
    }
}

02_LastDigitOfNumber.cs

using System;

/*
 * Write a method that returns the last digit of a given integer as an English word. 
 * Test the method with different input values. Ensure you name the method properly.
 */
 
class LastDigitOfNumber
{
    private static string GetLastDigitAsWord(int num)
    {
        string[] digitWords = { "zero", "one", "two", "three", "four",
                                  "five","six","seven","eight","nine"};

        int remainder = num % 10;

        return digitWords[remainder];
    }

    static void Main()
    {
        int number = int.Parse(Console.ReadLine());
        Console.WriteLine(GetLastDigitAsWord(number));
    }
}

03_LargerThanNeighbours.cs

using System;
using System.Linq;

/*
 * Write a method that checks if the element at given position 
 * in a given array of integers is larger than its two neighbours
 * (when such exist).
 */


class LargerThanNeighbours
{
    private static bool IsLargerThanNeighbours(int[] numbers, int i)
    {
        //check first element:
        if(i==0){
            if(numbers[0]>numbers[1])
                return true;
            else
                return false;
        }

        //check last element
        if (i == numbers.Length-1)
        {
            if (numbers[numbers.Length - 1] > numbers[numbers.Length - 2])
                return true;
            else
                return false;
        }

        //check other elements
        if (numbers[i] > numbers[i - 1] && numbers[i] > numbers[i + 1])
            return true;
        else
            return false;
        
    }

    static void Main()
    {
        Console.Write("Please, enter a sequence of space-separated integers: ");
        int[] numbers = Console.ReadLine().Trim().Split().Select(p => int.Parse(p)).ToArray();
        for (int i = 0; i < numbers.Length; i++)
        {
            Console.WriteLine(IsLargerThanNeighbours(numbers, i));
        }

    }
}

04_FirstLargerThanNeighbours.cs

using System;
using System.Linq;

/*
 * Write a method that returns the index of the first element in array that is larger
 * than its neighbours, or -1 if there's no such element. Use the method 
 * from the previous exercise
 */

class FirstLargerThanNeighbours
{
    private static bool IsLargerThanNeighbours(int[] numbers, int i)
    {
        //check first element:
        if (i == 0)
        {
            if (numbers[0] > numbers[1])
                return true;
            else
                return false;
        }

        //check last element
        if (i == numbers.Length - 1)
        {
            if (numbers[numbers.Length - 1] > numbers[numbers.Length - 2])
                return true;
            else
                return false;
        }

        //check other elements
        if (numbers[i] > numbers[i - 1] && numbers[i] > numbers[i + 1])
            return true;
        else
            return false;
    }

    private static int GetFirstElementLargerThanNeighbours(int[] array)
    {
        for (int i = 0; i < array.Length; i++)
        {
            if (IsLargerThanNeighbours(array, i))
            {
                return i;
            }
        }
        return -1;
    }

    static void Main()
    {
        Console.Write("Please, enter a sequence of space-separated integers: ");
        int[] numbers = Console.ReadLine().Trim().Split().Select(p => int.Parse(p)).ToArray();
        int indexFirstLarger = GetFirstElementLargerThanNeighbours(numbers);
        Console.WriteLine("Index of first larger element: " + indexFirstLarger);
    }
}

05_ReverseNumber.cs

using System;

/*
 * Write a method that reverses the digits of a given floating-point number.
 */

class ReverseNumber
{
    private static string ReverseString(string str)
    {
        if (str == null) 
            return "";
        char[] charArr = str.ToCharArray();
        Array.Reverse(charArr);
        return new string(charArr);
    }
    
    private static double GetReversedNumber(double num)
    {
        bool isNegative = num < 0;
        num = Math.Abs(num);
        string numStr = num.ToString();
        numStr = ReverseString(numStr);
        double result = double.Parse(numStr);
        return isNegative ? -result : result;
    }

    static void Main()
    {
        double num = double.Parse(Console.ReadLine());
        double revNum = GetReversedNumber(num);
        Console.WriteLine(revNum);
    }
}

06_NumberCalculations.cs

using System;
using System.Linq;

class NumberCalculations
{
    private static int minimum(int[] array)
    {
        int min = int.MaxValue;
        for (int i = 0; i < array.Length; i++)
            if (array[i] < min)
                min = array[i];
        return min;
    }

    private static int maximum(int[] array)
    {
        int max = int.MinValue;
        for (int i = 0; i < array.Length; i++)
            if (array[i] > max)
                max = array[i];
        return max;

    }

    private static double average(int[] array)
    {
        if (array.Length == 0) return 0.0;
        return ((double)sum(array)) / array.Length;
    }

    private static int sum(int[] array)
    {
        int result = 0;
        for (int i = 0; i < array.Length; i++)
        {
            result += array[i];
        }
        return result;
    }

    private static int product(int[] array)
    {
        int result = 1;
        for (int i = 0; i < array.Length; i++)
        {
            result *= array[i];
        }
        return result;
    }

    //double
    private static double minimum(double[] array)
    {
        double min = double.MaxValue;
        for (int i = 0; i < array.Length; i++)
            if (array[i] < min)
                min = array[i];
        return min;
    }

    private static double maximum(double[] array)
    {
        double max = double.MinValue;
        for (int i = 0; i < array.Length; i++)
            if (array[i] > max)
                max = array[i];
        return max;

    }

    private static double average(double[] array)
    {
        if (array.Length == 0) return 0.0;
        return ((double)sum(array)) / array.Length;
    }

    private static double sum(double[] array)
    {
        double result = 0;
        for (int i = 0; i < array.Length; i++)
        {
            result += array[i];
        }
        return result;
    }

    private static double product(double[] array)
    {
        double result = 1;
        for (int i = 0; i < array.Length; i++)
        {
            result *= array[i];
        }
        return result;
    }

    static void Main()
    {
        Console.Write("Please, enter a sequence of space-separated integers: ");
        int[] intNumbers = Console.ReadLine().Trim().Split().Select(p => int.Parse(p)).ToArray();
        Console.WriteLine("Integer array minimum: {0}", minimum(intNumbers));
        Console.WriteLine("Integer array maximum: {0}", maximum(intNumbers));
        Console.WriteLine("Integer array average: {0}", average(intNumbers));
        Console.WriteLine("Integer array sum: {0}", sum(intNumbers));
        Console.WriteLine("Integer array product: {0}", product(intNumbers));

        Console.Write("Please, enter a sequence of space-separated doubles: ");
        double[] doubleNumbers = Console.ReadLine().Trim().Split().Select(p => double.Parse(p)).ToArray();
        Console.WriteLine("Double array minimum: {0}", minimum(doubleNumbers));
        Console.WriteLine("Double array maximum: {0}", maximum(doubleNumbers));
        Console.WriteLine("Double array average: {0}", average(doubleNumbers));
        Console.WriteLine("Double array sum: {0}", sum(doubleNumbers));
        Console.WriteLine("Double array product: {0}", product(doubleNumbers));
    }
}

07_GenericArraySort.cs

using System;

/*
 * Write a method which takes an array of any type and sorts it. 
 * Use bubble sort or selection sort (your own implementation). 
 * You may re-use your code from a previous homework and modify it. 
 * Use a generic method (read in Internet about generic methods in C#). 
 * Make sure that what you're trying to sort can be sorted – 
 * your method should work with numbers, strings, dates, etc., 
 * but not necessarily with custom classes like Student.
 */

class GenericArraySort
{
    private static void GenericBubbleSort<T>(T[] genericArr) where T : IComparable
    {
        int len = genericArr.Length;
        for (int i = 0; i < len; i++)
        {
            for (int j = 0; j < len-1; j++)
            {
                if (genericArr[j].CompareTo(genericArr[j+1]) > 0)
                {
                    T temp = genericArr[j];
                    genericArr[j] = genericArr[j+1];
                    genericArr[j+1] = temp;
                }
            }
        }
    }



    static void Main()
    {
        String line="";
        DateTime[] dates = 
        {
            new DateTime(1969,7,8), new DateTime(1970,12,1), new DateTime(2005,11,22)
        };
        GenericBubbleSort(dates);
        line = string.Join(", ", dates);
        Console.WriteLine(line);
        
        int[] intArr = new int[] { -5, 8, 2, -1, 5, 0, 7};
        GenericBubbleSort(intArr);
        line = string.Join(", ", intArr);
        Console.WriteLine(line);

        string[] names = new string[] {"John", "Peter", "Alex", "Иван", "Петър", "Алекс" };
        GenericBubbleSort(names);
        line = string.Join(", ", names);
        Console.WriteLine(line);
    }
}