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

# Example 2D array representing the scores
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
]

public class popcornhack1 {
    public static void main(String[] args) {
        // 2D array representing the scores
        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]; // Get 92 from row 3, column 1
        int score70 = scores[4][3]; // Get 70 from row 5, column 4
        int score93 = scores[6][3]; // Get 93 from row 7, column 4

        scores[6][3] = 100; // Update row 7, column 4 to 100

        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] + " ");  
            }
            System.out.println(); 
        }
    }
}

popcornhack1.main(null);

Updated Scores:
85 95 96 
100 100 95 
100 98 100 
100 97 99 
100 100 70 
100 99 98 
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