Prerequisites: Arrays in Java, Array Declarations in Java (Single and Multidimensional)
Method 1 (Simple Traversal)
We can find the number of rows in a matrix mat[][] using mat.length. To find the number of columns in i-th row, we use mat[i].length.
Java
// Java program to print the elements of// a 2 D array or matriximport java.io.*;class GFG { public static void print2D(int mat[][]) { // Loop through all rows for (int i = 0; i < mat.length; i++) // Loop through all elements of current row for (int j = 0; j < mat[i].length; j++) System.out.print(mat[i][j] + " "); } public static void main(String args[]) throws IOException { int mat[][] = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 } }; print2D(mat); }} |
1 2 3 4 5 6 7 8 9 10 11 12
Time Complexity: O(N*M) where N is the number of rows in the matrix and M is the number of columns in the matrix.
Auxiliary Space: O(1)
Method 2 (Using for-each loop)
This is similar to the above. Instead of simple for loops, we use for each loop here.
Java
// Java program to print the elements of// a 2 D array or matrix using for-eachimport java.io.*;class GFG { public static void print2D(int mat[][]) { // Loop through all rows for (int[] row : mat) // Loop through all columns of current row for (int x : row) System.out.print(x + " "); } public static void main(String args[]) throws IOException { int mat[][] = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 } }; print2D(mat); }} |
1 2 3 4 5 6 7 8 9 10 11 12
Time Complexity: O(N*M) where N is the number of rows in the matrix and M is the number of columns in the matrix.
Auxiliary Space: O(1)
Method 3 (Prints in matrix style Using Arrays.toString())
Arrays.toString(row) converts the complete row is converted as a string and then each row is printed in a separate line.
Java
// Java program to print the elements of// a 2 D array or matrix using toString()import java.io.*;import java.util.*;class GFG { public static void print2D(int mat[][]) { // Loop through all rows for (int[] row : mat) // converting each row as string // and then printing in a separate line System.out.println(Arrays.toString(row)); } public static void main(String args[]) throws IOException { int mat[][] = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 } }; print2D(mat); }} |
[1, 2, 3, 4] [5, 6, 7, 8] [9, 10, 11, 12]
Time Complexity: O(N*M)
Auxiliary Space: O(1)
Method 4 (Prints in matrix style Using Arrays.deepToString())
Arrays.deepToString(int[][]) converts 2D array to string in a single step.
Java
// Java program to print the elements of// a 2 D array or matrix using deepToString()import java.io.*;import java.util.*;class GFG { public static void print2D(int mat[][]) { System.out.println(Arrays.deepToString(mat)); } public static void main(String args[]) throws IOException { int mat[][] = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 } }; print2D(mat); }} |
[[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
Time Complexity: O(N*M)
Auxiliary Space: O(1)
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