Accessing and Updating Elements in a 2D Array

Important Tips to Remember:

•	Array indices start at 0: The first row and first column are at index 0.
•	Relative positions: Always subtract 1 to determine the correct index relative to the 1-based numbering.

Accessing Elements

To access an element in a 2D array, use the following format:

arr[row][column]

Updating Elements

To update an element in a 2D array, assign a new value using this format:

variable_name[row][column] = new_value

For example: If you want to change the value in the second row and third column, use:

array[1][2] = new_value

Popcorn Hack:

Write code to access the scores: 92, 70, 93 and change the last score to 100

int[][] scores = {
    {100, 85, 95, 96},  // Student0
    {98, 100, 100, 95}, // Student1
    {92, 100, 98, 100}, // Student2
    {100, 100, 97, 99}, // Student3
    {100, 100, 100, 70},// Student4
        {100, 100, 99, 98}, // Student5
{100, 94, 100, 93}  // Student6
};

int score92 = scores[2][0]; // Student2, first score
int score70 = scores[4][3]; // Student4, last score
int score93 = scores[6][3]; // Student6, last score

System.out.println("Score 92: " + score92);
System.out.println("Score 70: " + score70);
System.out.println("Score 93 (before update): " + score93);

scores[6][3] = 100;

System.out.println("Score 93 (after update): " + scores[6][3]);

System.out.println("Updated scores:");
for (int i = 0; i < scores.length; i++) {
    for (int j = 0; j < scores[i].length; j++) {
        System.out.print(scores[i][j] + " ");
    }
}

Score 92: 92
Score 70: 70
Score 93 (before update): 93
Score 93 (after update): 100
Updated scores:
100 85 95 96 98 100 100 95 92 100 98 100 100 100 97 99 100 100 100 70 100 100 99 98 100 94 100 100 

Essential points:

When accessing elements at arr[first][second], the first index is used for rows, and the second index is used for columns
Square brackets [row][col] are used to access and modify an element of a 2d array.

2D Arrays - accessing and updating elements