Two- Dimensional Array

I am new in java programming. I am creating a two-dimensional array. This is my code
**
class BinaryNumbers
{
public static void main(String[] args)
{
//create a two-dimensional array
int ROWS = 21;
int COLS = 2;

int[][] a2 = new int[ROWS][COLS];

//... Print array in rectangular form
for (int i =0; i < ROWS; i++) {
for (int j = 0; j < COLS; j++) {
System.out.print(" " + a2[i][j]);
}
System.out.println("");
}
}
}
I want to enter this data into this array
Decimal Binary
1 1
2 10
3 11
4 100
5 101
6 110
7 111
8 1000
9 1001
10 1010
11 1011
12 1100
13 1101
14 1110
15 1111
16 10000
17 10001
18 10010
19 10011
20 10100
how can i do this? Please help me

View Answers

February 22, 2010 at 12:48 PM

Hi Friend,

Try the following code:

class BinaryNumbers
{
static int ROWS = 20;
static int COLS = 2;
public static void main(String[] args){
int a2[][]={{1,1},{2,10},{3,11},{4,100},{5,101},{6,110},{7,111},{8,1000},{9,1001},{10,1010},{11,1011},
{12,1100},{13,1101},{14,1110},{15,1111},{16,10000},{17,10001},{18,10010},{19,10011},{20,10100}};
System.out.println("Decimal Binary");
for (int i =0; i < ROWS; i++) {
for (int j = 0; j < COLS; j++) {
System.out.print(" " + a2[i][j]);
}
System.out.println("");
}
}
}

Thanks

February 23, 2010 at 12:00 AM

Hey,
Here is the code which builds Binary Numbers dynamically where you need not give binary numbers explicitly. Just the decimal no. is sufficient.

public class BinaryNumbers {

public static void main(String[] args) {
int ROWS = 26;
int COLS = 2;
int[][] binaryArray = new int[ROWS][COLS];
for (int i = 1; i < ROWS; i++) {
String binaryNo = Integer.toBinaryString(i);
for (int j = 0; j < COLS - 1; j++) {
binaryArray[i][j] = i;
binaryArray[i][++j] = Integer.parseInt(binaryNo);
}
}
for (int i = 1; i < ROWS; i++) {
for (int j = 0; j < COLS; j++) {
System.out.print(binaryArray[i][j] + " ");
}
System.out.println("");
}
}

}

February 23, 2010 at 12:17 AM

Hi,
Here is another code same as above that prints binary numbers on the fly with little modification.
Just give how many no.of binary numbers you wanna print starting from 1 in the console.May seem complex, but easy..

import java.util.Scanner;

public class BinaryNumbers {

public static void main(String[] args) {
System.out
.println("Enter the no. of binary numbers you want to print : ");
Scanner scan = new Scanner(System.in);
int ROWS = scan.nextInt() + 1;
int[][] binary = new int[ROWS][];
for (int i = 1; i < ROWS; i++) {
String binaryNo = Integer.toBinaryString(i);
binary[i] = new int[2];
binary[i][0] = i;
binary[i][1] = Integer.parseInt(binaryNo);
}
/* Print Array */
for (int i = 1; i < ROWS; i++) {
System.out.println(binary[i][0] + " " + binary[i][1]);
}
}
}

Snippet of o/p:

Enter the no. of binary numbers you want to print :
40
1 1
2 10
3 11
4 100
.
.
.
38 100110
39 100111
40 101000

Regards,
javaquest2010

February 26, 2010 at 7:32 AM

Thank you very much every one