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## Example: printing out the elements of a matrix ordered by rows and by columns

We develop two static methods, printMatrixRows() and printMatrixColumns(), that take as parameter a matrix and print out its elements ordered respectively per rows and per columns.

```public static void printMatrixRows(short[][] m) {
for (int i = 0; i < m.length; i++) {    // iterates over the rows
for (int j = 0; j < m[0].length; j++) // iterates over the elements of row i
System.out.print(m[i][j] + " ");    // prints the element
System.out.println();                 // end of the row
}
}
```

Note that, in order to access all elements of the matrix m, we use two nested for loops: the outermost loop iterates over the rows (using control variable i), while the innermost loop iterates over the elements of row i (using control variable j). At the end of each row, a newline character is printed out.

```public static void printMatrixColumns(short[][] m) {
for (int j = 0; j < m[0].length; j++) { // iterates over the columns
for (int i = 0; i < m.length; i++)    // iterates over the elements of col j
System.out.print(m[i][j] + " ");    // prints the element
System.out.println();                 // end of the column
}
}
```

Also in this case, we use two nested for loops: the outermost loop iterates over the columns (using control variable j), while the innermost loop iterates over the elements of column i (using control variable j). At the end of each column, a newline character is printed out.

Example of usage:

```public static void main(String[] args) {
short[][] A = {          // creates a matrix A of dimension 2x3
{ 1, 2, 2 },           // row 0 of A (array of 3 short)
{ 7, 5, 9 }            // row 1 of A (array of 3 short)
};
printMatrixRows(A);      // prints out the matrix row by row
System.out.println();
printMatrixColumns(A);   // prints out the matrix column by column
}
```

The program prints out the following:

```1 2 2
7 5 9

1 7
2 5
2 9
```

Next: Example: sum of two Up: Unit 07 Previous: Number of rows and