ArrayExercises.java

import java.util.Scanner;
//*******************************************************
// ArrayExercises.java
// The class have solutions to array exercises
// Author: liron mizrahi
//*******************************************************
public class ArrayExercises
{
    public static void main(String[] args) 
    {
        //make scan object
        Scanner scan = new Scanner(System.in);
        int choise;
        boolean fcontinue = true;

        // do while
        do
        {
            //menu
            System.out.println("Please Choose one of the following loops exercises: ");
            System.out.println("1 - For exercise 6");
            System.out.println("2 - For exercise 7");
            System.out.println("3 - For exercise 8");
            System.out.println("4 - For exercise 11");
            System.out.println("5 - For exercise 13");
            System.out.println("6 - For exercise 2");
            System.out.println("7 - For exercise 3");
            System.out.println("8 - For exercise 7");
            System.out.println("0 - To Exit " + "\n");
            System.out.println("Enter your choise --->  ");
            // take input from user
            choise = scan.nextInt();

            //switch case
            switch (choise)
            {
                case 1:
                {
                    //here code of Exercise 6
                    // take user input
                    System.out.print("enter the len of the array");
                    int len = scan.nextInt();
                    // make array
                    int[] arr1 = new int[len];
                    int[] arr2 = new int[len];
                    // insert valus to arrays
                    for(int i = 0; i < len; i++)
                    {
                        arr1[i] = scan.nextInt();
                    }

                    for(int j = 0; j < len; j++)
                    {
                        arr2[j] = scan.nextInt();
                    }

                    System.out.println(isArrShift(arr1, arr2) + " ");
                    break;
                }//end of case 1
                case 2:
                {
                    //here code of Exercise 7

                    char[] charArr = {'A', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'L'};

                    makeUpperCase(charArr);
                    for(int i = 0; i < charArr.length; i++)
                    {
                        System.out.print(charArr[i]);
                    }    
                    System.out.println(" ");
                    break;
                }//end of case 2
                case 3:
                {
                    //here code of Exercise 8
                    // take user input
                    System.out.print("enter the len of first array");
                    int len3 = scan.nextInt();
                    System.out.print("enter the len of second array");
                    int len4 = scan.nextInt();

                    // make array
                    int[] arr3 = new int[len3];
                    int[] arr4 = new int[len4];
                    // insert valus to arrays
                    for(int i = 0; i < len3; i++)
                    {
                        arr3[i] = scan.nextInt();
                    }

                    for(int j = 0; j < len4; j++)
                    {
                        arr4[j] = scan.nextInt();
                    }

                    int[] arr5 = intersectionValusArr(arr3, arr4);
                    // print the arr 
                    for(int i = 0;  i < arr5.length; i++)
                    {
                        System.out.print(arr5[i]);
                    }
                    System.out.println(" ");
                    break;
                }//end of case 3
                case 4:
                {
                    //here code of Exercise 11
                    // take user input
                    System.out.print("enter the len of the array");
                    int len6 = scan.nextInt();
                    // make array
                    int[] arr6 = new int[len6];
                    for (int i=0; i < arr6.length; i++  )
                    {
                        arr6[i] = scan.nextInt();
                    }
                    printArrStar(arr6);
                    System.out.println(" ");
                    break;
                }//end of case 4
                case 5:
                {
                    //here code of Exercise 13
                    //take user input
                    System.out.print("enter the len of first array");
                    int len7 = scan.nextInt();
                    System.out.print("enter the len of second array");
                    int len8 = scan.nextInt();

                    // make array
                    int[] arr7 = new int[len7];
                    int[] arr8 = new int[len8];
                    for (int i = 0; i < arr7.length; i++)
                    {
                        arr7[i] = scan.nextInt();
                    }
                    for (int i = 0; i < arr8.length; i++)
                    {
                        arr8[i] = scan.nextInt();
                    }
                    int[] arr9 = multiplyNumbers(arr7, arr8);
                    for(int i = 0; i < arr9.length; i++)
                    {
                        System.out.print(arr9[i]);
                    }
                    System.out.println(" ");
                    break;
                }//end of case 5
                case 6:
                {
                    //here code of Exercise 2
                    // take user input
                    System.out.print("enter the len of rows");
                    int rows = scan.nextInt();
                    System.out.print("enter the len of columns");
                    int columns = scan.nextInt();
                    int[][] matrix = new int[rows][columns];
                    for(int i = 0; i < rows; i++)
                    {
                        for(int j = 0; j < columns; j++)
                        {
                            matrix[i][j] = scan.nextInt();
                        }
                    }
                    System.out.println(maxValueInFrame(matrix));

                    break;
                }//end of case 6
                case 7:
                { 
                    //hare code of Exercise 3
                    //here code of Exercise 2
                    // take user input
                    System.out.print("enter the len of rows");
                    int rows1 = scan.nextInt();
                    System.out.print("enter the len of columns");
                    int columns1 = scan.nextInt();
                    fillMatrix(rows1, columns1);

                    break;
                }//end of case 7
                case 8:
                {
                    //hare code of Exercise 7
                    char[][] charArr = 
                        {
                            {'a', 'a', 'a', '|', '-', '-'},
                            {'a', 'a', 'a', '|', 'a', 'a'},
                            {'|', '-', '-', '-', 'a', 'a'},
                            {'|', 'a', 'a', 'a', 'a', 'a'},
                            {'|', 'a', 'a', 'a', 'a', 'a'},
                        };
                    System.out.println(isWay(charArr));
                    break;
                }//end of case 8
                case 0:
                {
                    fcontinue = false;
                }
                default:
                {
                    System.out.println("Invalid option");
                }
            }            
        } 
        while (fcontinue);
        System.out.println("Goodbye");
    } //end of method main

    //Ex6 function
    /**
     * method return true if the arr values shift by 1 
     * @param: intp[ arr1, int[] arr2
     * @return: boolean 
     */
    public static boolean isArrShift(int[] arr1, int[] arr2)
    {

        for (int i=0; i < arr1.length; i++)
        {
            if(i == arr1.length - 1)
            {
                if(arr1[i] != arr2[0])
                {
                    return false;
                }
            }
            else if(arr1[i] != arr2[i + 1])
            {
                return false;
            }
        }
        return true;
    }// end of method isArrShift

    //Ex7 function
    /**
     * method make the values in the array ypper case 
     * @param: char[] arr
     * @return: None
     */
    public static void makeUpperCase(char[] arr)
    {
        int startIndex = 0;
        int endIndex = 0;
        int flag = 0;
        for(int i = 0; i < arr.length; i++)
        {
            if(flag == 1)
            {
                if(Character.isUpperCase(arr[i]))
                {
                    endIndex = i;
                    flag--;
                }
            }
            else if(flag == 0)
            {
                if(Character.isUpperCase(arr[i]))
                {
                    startIndex = i;
                    flag++;
                }
            }
        }
        for(int j = startIndex + 1; j < endIndex; j++)
        {
            arr[j] = Character.toUpperCase(arr[j]);
        }
    }// end of method makeUpperCase
    //Ex8
    /**
     * method return the intersection Arr
     * @param: int[] arr1, int[] arr2
     * @return: int[]
     */
    public static int[] intersectionValusArr(int[] arr1, int[] arr2)
    {
        arr1 = sortArr(arr1);
        arr2 = sortArr(arr2);
        int lenIntersectionArr = lenIntersectionArr(arr1, arr2);
        int[] intersectionArr = new int[lenIntersectionArr];
        int intersectionIndex = 0;
        for(int i = 0; i < arr1.length; i++)
        {
            for(int j = 0; j < arr2.length; j++)
            {
                if(arr1[i] == arr2[j])
                {
                    intersectionArr[intersectionIndex] = arr1[i];
                    intersectionIndex++;
                }
            }
        }
        return intersectionArr;
    }// end of method intersectionValuesArr
    /**
     * method return the len of the intersection array
     * @param: int[] arr1, int[] arr2
     * @return: int
     */
    private static int lenIntersectionArr(int[] arr1, int[] arr2)
    {
        int i = 0, j = 0, lenIntersectionArr = 0;
        while(i < arr1.length && j < arr2.length)
        {
            if(arr1[i] < arr2[j])
            {
                i++;
            }
            else if(arr2[j] < arr1[i])
            {

                j++;
            }
            else
            {
                lenIntersectionArr++;
                i++;
            }
        }
        return lenIntersectionArr;
    }// end of method lenIntersectionArr
    /**
     * method sort the array
     * @param: int[] arr
     * @return: int[]
     */
    private static int[] sortArr(int[] arr)
    {
        for(int i = 0; i < arr.length; i++)
        {
            for(int j = 1; j < arr.length - i ; j++)
            {
                if(arr[i] > arr[j])
                {
                    int temp = arr[j];
                    arr[j] = arr[i];
                    arr[i] = temp;
                }
            }
        }
        return arr;
    }// end of method sortArr
    //Ex11
    /**
     * method print the array like a star tower
     * @param: int[] arr
     * @return: None
     */
    public static void printArrStar(int[] arr)
    {
        int maxValue = 0;
        for(int value : arr)
        {
            if(value > maxValue)
            {
                maxValue = value;
            }
        }
        int index = maxValue;
        while(index > 0)
        {
            System.out.println(" ");
            for(int i = 0; i < arr.length; i++)
            {
                if(index <= arr[i])
                {
                    System.out.print(" *");
                }
                else
                {
                    System.out.print("  ");
                }
            }
            System.out.println();
            index -= 1;
        }
        System.out.print(" ");
        for(int i = 0; i < arr.length; i++)
        {
            System.out.print("__");
        }
        System.out.println("");
        System.out.print(" ");
        for(int i = 0; i < arr.length; i++)
        {
            System.out.print(arr[i] + " ");
        }
    }// end of method printArrStar
    //Ex13
    /**
     * method multiply the numbers of the two array and insert to the 3 array
     * @param: int[] num1, int[] num2
     * @return: int[]
     */
    public static int[] multiplyNumbers(int[] num1, int[] num2)
    {
        int sum = 0;
        for(int i = 0; i < num1.length; i++)
        {
            for(int j = 0; j < num2.length; j++)
            {
                sum += Math.pow(10, num1.length - i - 1) * num1[i] * Math.pow(10, num2.length - j - 1) * num2[j];
            }
        }
        int lenMultiplyArr = 0;
        int copySum = sum;
        while(copySum > 0)
        {
            lenMultiplyArr++; 
            copySum /= 10;
        }
        int[] multiplyArr = new int[lenMultiplyArr];
        for(int k = lenMultiplyArr - 1; k >= 0; k--)
        {
            int lastDigit = sum % 10;
            multiplyArr[k] = lastDigit;
            sum /= 10;
        }
        return multiplyArr;
    }// multiplyNumbers
    //Ex2
    /**
     * method return the max value in frame of the given matrix
     * @param: int[][] arr
     * @return: int
     */
    public static int maxValueInFrame(int[][] arr)
    {
        int max = Integer.MIN_VALUE;
        for(int i = 0; i < arr.length; i += arr.length - 1)
        {
            for(int j = 0; j < arr[i].length; j++)
            {
                if(arr[i][j] > max)
                {
                    max = arr[i][j];
                }
            }
        }

        for(int i = 0; i < arr.length; i++)
        {
            if(arr[i][0] > max)
            {
                max = arr[i][0];
            }
        }

        for(int i = 0; i < arr.length; i++)
        {
            if(arr[i][arr[i].length -1] > max)
            {
                max = arr[i][arr[i].length -1];
            }
        }

        return max;
    }// end of method maxValueInFrame
    //Ex3
    /**
     * method fill the matrix in snake pattern
     * @param: int rows, int cols
     * @return: None
     */
    public static void fillMatrix(int rows, int cols)
    {
        int[][] matrix = new int[rows][cols];
        int flag = 2;
        if(cols % 2 == 0)
        {
            flag = 1;
        }
        else 
        {
            flag = 0;
        }
        int num = 1;
        for( int j = cols - 1; j >= 0; j--)
        {
            if(flag == 1)
            {
                if(j % 2 != 0)
                {
                    // fill the column top to bottom
                    for(int i = 0; i < rows; i++)
                    {
                        matrix[i][j] = num++;
                    }
                }
                else
                {
                    // fill the column bottom to top
                    for(int i = rows - 1; i >= 0; i--)
                    {
                        matrix[i][j] = num++;
                    }
                } 
            }
            else
            {
                if(j % 2 == 0)
                {
                    // fill the column top to bottom
                    for(int i = 0; i < rows; i++)
                    {
                        matrix[i][j] = num++;
                    }
                }
                else
                {
                    // fill the column bottom to top
                    for(int i = rows - 1; i >= 0; i--)
                    {
                        matrix[i][j] = num++;
                    }
                } 
            }
        }

        for(int i = 0; i < rows; i++)
        {
            for(int j = 0; j < cols; j++)
            {
                System.out.print(matrix[i][j] + " ");
            }
            System.out.println();
        }
    }// end of method fillMatrix
    //Ex7
    /**
     * method return true if there are a way otherwise false 
     * @param: char[][] arr
     * @return: boolean
     */
    public static boolean isWay(char[][] arr)
    {
        if(arr[0][arr[0].length - 1] != '|' && arr[0][arr[0].length - 1] != '-')
        {
            return false; 
        }
        int cols = arr[0].length - 1; // 5
        for(int i = 0; i < arr.length; i++) // 4, 4 < 5
        {
            if( i == arr.length - 1)
            {
                if(arr[i][cols] == '|')
                {
                    return true;
                }
                else if(arr[i][cols] == '-')
                {
                    cols--;
                }
                else
                {
                    return false;
                }
            }
            if(arr[i][cols] != '-') 
            {
                if(arr[i][cols] != '|') 
                {
                    return false;
                }
            }
            else
            {
                cols = cols -1;
                if( cols < 0)
                {
                    return false;
                }
                i--;
            }
        }
        return true;
    }// end of method isWay
}// end of class ArrayExercises