Arrays 2

Multidimensional Arrays

Ex-1
Ex-2
Ex-3
Ex-4

int[][] a = new int[3][4];

int n = 5;
int[][] distance = new int[n][n];
distance[0][1] = distance[1][0] = 10;
distance[1][3] = distance[3][1] = 5;

int[][] a = {
    {1, 2, 3},
    {4, 5, 6, 9},
    {7},
};

int[][] data = new int[4][];
data[0] = new int[3];
data[1] = new int[10];
data[2] = new int[2];
data[3] = new int[6];

Array Traversal

int[][] data = {
    { 1, 2, 3 },
    { 4, 5 },
    { 6, 7, 8, 9 }
};

for (int i = 0; i < data.length; i++) {
    for (int j = 0; j < data[i].length; j++) {
        System.out.print(data[i][j] + "\t");
    }
    System.out.println();
}

int[][] array2D = {
    { 1, 2, 3 },
    { 4, 5 },
    { 6, 7, 8, 9 }
};

for (int[] array1D : array2D) {
    for (int elem : array1D) {
        System.out.print(elem + "\t");
    }
    System.out.println();
}

Exercise

Exercise 1

Question
Answer

Create an array that can hold $n$ integers
Fill up the array with user inputs
Ask the user to enter a value that they want to find
Show if the value is in the array

  import java.util.Scanner;
  public class Main {
  	public static void main(String[] args) {
  		Scanner sc = new Scanner(System.in);
  		System.out.print("Enter the length of array: ");
  		int n = sc.nextInt();
  		int[] arr = new int[n];
  		System.out.println("Enter the elements of the array: ");
  		for (int i = 0; i < n; i++) {
  			arr[i] = sc.nextInt();
  		}
  		System.out.print("Enter the lookup value: ");
  		int lookup = sc.nextInt();
  		for (int i = 0; i < n; i++) {
  			if (arr[i] == lookup) {
  				System.out.println(lookup + " is in the array.");
  			}
  		}
  	}
  }

Exercise 2

Question
Answer

Create an array that can hold $n$ integers
Fill up the array with user inputs
Ask the user to enter a value that they want to find
Show how many times the value appears in the array

  import java.util.Scanner;
  public class Main {
  	public static void main(String[] args) {
  		Scanner sc = new Scanner(System.in);
  		System.out.print("Enter the length of array: ");
  		int n = sc.nextInt();
  		int[] arr = new int[n];
  		System.out.println("Enter the elements of the array: ");
  		for (int i = 0; i < n; i++) {
  			arr[i] = sc.nextInt();
  		}
  		System.out.print("Enter the lookup value: ");
  		int lookup = sc.nextInt();
  		int count = 0;
  		for (int i = 0; i < n; i++) {
  			if (arr[i] == lookup) {
  				count++;
  			}
  		}
  		System.out.println(lookup + " appears " + count + " time(s) in the array.");
  	}
  }

Exercise 3

Question
Answer

Create an array that can hold $n$ integers
Fill up the array with user inputs
Ask the user to enter a value that they want to find
Show whether the value is in the array or not

  import java.util.Scanner;
  public class Main {
  	public static void main(String[] args) {
  		Scanner sc = new Scanner(System.in);
  		System.out.print("Enter the length of array: ");
  		int n = sc.nextInt();
  		int[] arr = new int[n];
  		System.out.println("Enter the elements of the array: ");
  		for (int i = 0; i < n; i++) {
  			arr[i] = sc.nextInt();
  		}
  		System.out.print("Enter the lookup value: ");
  		int lookup = sc.nextInt();
  		boolean found = false;
  		for (int i = 0; i < n; i++) {
  			if (arr[i] == lookup) {
  				found = true;
  				break;
  			}
  		}
  		if (found) {
  			System.out.println(lookup + " is in the array.");
  		} else {
  			System.out.println(lookup + " is not in the array.");
  		}
  	}
  }

Exercise 4

Question
Answer

Create an array that can hold $n$ integers
Fill up the array with user inputs
Ask the user to enter a value that they want to find
Show on which index the value appears in the array

  import java.util.Scanner;
  public class Main {
  	public static void main(String[] args) {
  		Scanner sc = new Scanner(System.in);
  		System.out.print("Enter the length of array: ");
  		int n = sc.nextInt();
  		int[] arr = new int[n];
  		System.out.println("Enter the elements of the array: ");
  		for (int i = 0; i < n; i++) {
  			arr[i] = sc.nextInt();
  		}
  		System.out.print("Enter the lookup value: ");
  		int lookup = sc.nextInt();
  		boolean found = false;
  		for (int i = 0; i < n; i++) {
  			if (arr[i] == lookup) {
  				found = true;
  				System.out.println(lookup + " is at index " + i + ".");
  			}
  		}
  		if (!found) {
  			System.out.println(lookup + " is not in the array.");
  		}
  	}
  }

Exercise 5

Question
Answer

Create an array that can hold $n$ integers
Fill up the array with user inputs
Find the largest value in the array
Also display on which index the maximum value appears in the array

  import java.util.Scanner;
  public class Main {
  	public static void main(String[] args) {
  		Scanner sc = new Scanner(System.in);
  		System.out.print("Enter the length of array: ");
  		int n = sc.nextInt();
  		int[] arr = new int[n];
  		System.out.println("Enter the elements of the array: ");
  		for (int i = 0; i < n; i++) {
  			arr[i] = sc.nextInt();
  		}
  		int max = arr[0];
  		int index = 0;
  		for (int i = 1; i < n; i++) {
  			if (arr[i] > max) {
  				max = arr[i];
  				index = i;
  			}
  		}
  		System.out.printf("Maximum value: %d", max);
  		System.out.printf("\nIndex: %d", index);
  	}
  }

Exercise 6

Question
Answer

Create a 2-dimensional array that can hold m x n integers
Fill up the array with user inputs
Display the contents of the array

  import java.util.Scanner;
  public class Main {
  	public static void main(String[] args) {
  		Scanner sc = new Scanner(System.in);
  		System.out.print("m: ");
  		int m = sc.nextInt();
  		System.out.print("n: ");
  		int n = sc.nextInt();
  		int[][] arr = new int[m][n];
  		System.out.println("Enter the elements of the array: ");
  		for (int i = 0; i < m; i++) {
  			for (int j = 0; j < n; j++) {
  				arr[i][j] = sc.nextInt();
  			}
  		}
  		System.out.println("Contents of the array:");
  		for (int i = 0; i < m; i++) {
  			for (int j = 0; j < n; j++) {
  				System.out.print(arr[i][j] + "\t");
  			}
  			System.out.println();
  		}
  	}
  }

Exercise 7

Question
Answer

Create a 2-dimensional array that can hold m x n integers
Fill up the array with user inputs
Ask the user to enter a value that they want to find
Show how many times the value appears in the array

  import java.util.Scanner;
  public class Main {
  	public static void main(String[] args) {
  		Scanner sc = new Scanner(System.in);
  		System.out.print("m: ");
  		int m = sc.nextInt();
  		System.out.print("n: ");
  		int n = sc.nextInt();
  		int[][] arr = new int[m][n];
  		System.out.println("Enter the elements of the array: ");
  		for (int i = 0; i < m; i++) {
  			for (int j = 0; j < n; j++) {
  				arr[i][j] = sc.nextInt();
  			}
  		}
  		System.out.print("Enter the lookup value: ");
  		int lookup = sc.nextInt();
  		int count = 0;
  		for (int i = 0; i < m; i++) {
  			for (int j = 0; j < n; j++) {
  				if (arr[i][j] == lookup) {
  					count++;
  				}
  			}
  		}
  		System.out.println(lookup + " appears " + count + " time(s) in the array.");
  	}
  }

Exercise 8

Question
Answer

Create a 2-dimensional array that can hold m x n integers
Fill up the array with user inputs
Find the largest value in the array
Also display on which index the maximum value appears in the array

  import java.util.Scanner;
  public class Main {
  	public static void main(String[] args) {
  		Scanner sc = new Scanner(System.in);
  		System.out.print("m: ");
  		int m = sc.nextInt();
  		System.out.print("n: ");
  		int n = sc.nextInt();
  		int[][] arr = new int[m][n];
  		System.out.println("Enter the elements of the array: ");
  		for (int i = 0; i < m; i++) {
  			for (int j = 0; j < n; j++) {
  				arr[i][j] = sc.nextInt();
  			}
  		}
  		int max = arr[0][0];
  		int maxI = 0;
  		int maxJ = 0;
  		for (int i = 0; i < m; i++) {
  			for (int j = 0; j < n; j++) {
  				if (arr[i][j] > max) {
  					max = arr[i][j];
  					maxI = i;
  					maxJ = j;
  				}
  			}
  		}
  		System.out.printf("Maximum value: %d\n", max);
  		System.out.printf("Index: (%d, %d)\n", maxI, maxJ);
  	}
  }

Persiapan Belajar

Materi

Task

Programming by Doing

Compiler

Multidimensional Arrays

Array Traversal

Exercise

Exercise 1

Exercise 2

Exercise 3

Exercise 4

Exercise 5

Exercise 6

Exercise 7

Exercise 8

​Multidimensional Arrays

​Array Traversal

​Exercise

​Exercise 1

​Exercise 2

​Exercise 3

​Exercise 4

​Exercise 5

​Exercise 6

​Exercise 7

​Exercise 8

Multidimensional Arrays

Array Traversal

Exercise

Exercise 1

Exercise 2

Exercise 3

Exercise 4

Exercise 5

Exercise 6

Exercise 7

Exercise 8