Thread: copying numbers stored in one 2d array into a new 2d array with different dimensions.

Here is the problem:

Write a program that creates a 2 dimensional array X containing 4*6 elements. Store numbers from 1-24 in the array. Create another array Y that can store 3*8 elements. Write a program that copies all the numbers from X to Y. Print both arrays.

This is what i have so far but the trick is i am not supposed to just create the new array with dimensions 3x8 i am supposed to copy the numbers from the 4x6 array into the new 3x8 array:

public class c2 {public static void main(String[]a){
 
	int [][]x=new int [4][6]; 
 
	int temp=1; 
	for(int i=0;i<=3;i++){ 
	for (int j=0;j<=5;j++){ 
	x[i][j]=temp;
	temp=temp+1;
 
		}
 
 
		}
	int [][]y=new int[3][8];
	int temp1=1;
	for(int b=0;b<=2;b++){ 
		for (int d=0;d<=7;d++){ 
			y[b][d]=temp1;
			temp1=temp1+1;
		}
	}
	for(int i=0;i<=3;i++){ 
		for (int j=0;j<=5;j++){ System.out.print(" " +x[i][j]);}
		System.out.println();
 
 
	}
	System.out.println();
	for(int b=0;b<=2;b++){ 
		for (int d=0;d<=7;d++){System.out.print(" " + y[b][d]);}
		System.out.println();
 
	}
 
 
}
}

Please don't post multiple threads with the same question. I already wasted time responding to your other one- which I've now deleted.

I'd suggest you draw out both arrays, labeling each index. That way you can see how they correspond to one another.

An easy enough solution of the top of the head would be to take the contents of the first array and store them in a temporary 1 dimensional array. Then transfer them over to your new array. Probably an easier way but its the first thing I thought of. I just threw the code into a pair of methods.

class Copy2dArray
{
	//Copies the contents of a 2d array into another 2d array
	//@PARAM The array to be copied and the two values determining the size of
	//the M * N sized array to be created. mDim = M, nDim = N.
	static int[][] copy2dArrayContents(int[][] original, int mDim, int nDim)
	{
		int[] arrayTemp = new int[mDim*nDim]; //nDim * mDim is the max amount of elements that the copy can store, as specified by user
		int[][] copy = new int[mDim][nDim]; //array with specified dimension to store the copied contents
		int tempIndex = 0;
 
		//Copy array1 contents into arrayTemp
		for(int i = 0; i < original.length; i++)
		{
			for(int j = 0; j < original[i].length; j++)
			{
				arrayTemp[tempIndex] = original[i][j];
				tempIndex++;
			}
		}
		tempIndex = 0;
 
		for(int i = 0; i < copy.length; i++)
		{
			for(int j = 0; j < copy[i].length; j++)
			{
				copy[i][j] = arrayTemp[tempIndex];
				tempIndex++;
			}
		}
 
		return copy;
 
	}
 
	//print out a 2d array to STD output
        //@PARAM The array to be printed
	static void print2dArray(int[][] array)
	{
		for(int i = 0; i < array.length; i++)
		{
			for(int j = 0; j < array[i].length; j++)
			{
				System.out.print(array[i][j] + " ");
			}
		}
		System.out.println("");
	}
 
	public static void main(String[] args) 
	{
		//Declare variables
		int[][] array1 = new int[4][6]; //Original array
		int[][] array2 = new int[3][8]; //Array to be copied to
		int start = 1;
 
		//Initialize array1 with numbers 1 - 24
		for(int i = 0; i < 4; i++)
		{
			for(int j = 0; j < 6; j++)
			{
				array1[i][j] = start;
				start++;
			}
		}
 
		//Copy array1 contents into array2
		array2 = copy2dArrayContents(array1, 3, 8);
 
		//print both arrays to standard output
		print2dArray(array1);
		print2dArray(array2);
	}
}

Resulting Output:

L:\Code\Java\java Copy2dArray
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24