Java: Find the all positions of a given number in a given matrix

Last update on May 13 2025 13:00:21 (UTC/GMT +8 hours)

Find Positions in Matrix

Write a Java program to determine the all positions of a given number in a given matrix. If the number is not found print ("Number not found!").

Visual Presentation:

Sample Solution:

Java Code:

// Main class for the solution
public class Solution {

    // Main method to execute the solution
    public static void main(String[] args) {
        // Initialize the target number
        int num = 3;

        // Initialize a 2D matrix
        int matrix[][] = {
            {2, 5, 3},
            {3, 2, 1},
            {1, 3, 5}
        };

        // Get the number of rows in the matrix
        int r = matrix.length;

        // Get the number of columns in the matrix
        int c = matrix[0].length - 1;

        // Initialize variables for matrix traversal
        int m = 0, n = 0;

        // Boolean flag to check if the number is found in the matrix
        Boolean flag = false;

        // Iterate through the rows of the matrix
        while (m < r) {
            // Iterate through the columns of the matrix
            while (n <= c) {
                // Check if the current element is equal to the target number
                if (matrix[m][n] == num) {
                    // Display the coordinates of the found number
                    System.out.print("\n(" + m + "," + n + ")\n");
                    // Set the flag to true indicating the number is found
                    flag = true;
                }
                // Move to the next column
                n++;
            }

            // Move to the next row and reset column index
            m++;
            n = 0;
        }

        // Display a message if the number is not found in the matrix
        if (flag == false)
            System.out.print("Number not found!");
    }
} 

Sample Output:

(0,2)

(1,0)

(2,1)

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to find all positions along the main diagonal of a matrix where the elements satisfy a given condition.
• Write a Java program to list the coordinates of all border elements in a matrix that match a specified value.
• Write a Java program to count and display the total number of occurrences of a given number in a matrix.
• Write a Java program to locate a given number in a matrix and output the coordinates of its immediate neighbors.

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