Re: System.arraycopy (2 dim array) and growth of 2 dim array
Denis Palas wrote:
Hi everybody
I am working on a program which contains a module that can perform Cartesian
product on number of sets.
The code I have developed so far is :
import java.lang.reflect.Array;
public class Cart5 {
public static void main(String[] args) throws Exception
{
int pubnewlength;
// declare SolArray
int[][] solArray;
// initialize solArray
solArray=new int[1][4];
// Use for method
for (int ii=0 ; ii<4 ; ii++)
solver(solArray,ii);
// Print the array ?
System.out.println("\n The array was changed ... " );
} // End main
// --------------------------------------------------------------------------
public void solver(int Solarray2[][] , int abi)
{
int[][] A = { {1,2,3,5},
{4,6,7},
{11,22,9,10},
{17,33}
};
jointwoArrays(solarray2,A,abi);
// some other operations
} // End Solver method
// ------------------------------------------------------------------------------
public void jointwoArrays(int solarray3[][] , int aArray[][],int indexA)
{
int y,u;
int[][] tempArray;
// calculate growth of rows:
pubnewlength=solArray3.length * aArray[indexA].length;
//Fill TempArray
y=solArray3[0].length;
u=solArray3.length;
tempArray=new int[u][y];
// Use system.arraycopy to copy solArray3 into tempArray -- How ?
// Change the size of arrow to proper size -- How ?
solArray3 = (int[][]) arrayGrow(solArray3);
// Join operation - Still under construction
for(int i = 0, k = 0; i < tempArray.length; i++)
for(int j = 0; j < set3.length; j++)
{
for (q=0;q<=2;q++)
{ solArray3[k][q] = tempArray[i][q];}
solArray3[k][q]= aArray[indexA][j];
++k;
}
} // End jointwoArrays method
// -----------------------------------------------------------------------------------
// This module is from
http://www.java2s.com/ExampleCode/Language-Basics/Growarray.htm
static Object arrayGrow(Object a) {
Class cl = a.getClass();
if (!cl.isArray())
return null;
Class componentType = a.getClass().getComponentType();
int length = Array.getLength(a);
int newLength = pubnewlength;
Object newArray = Array.newInstance(componentType, newLength);
System.arraycopy(a, 0, newArray, 0, length);
return newArray;
}
} // End Class
I deeply appreciate your help with these 3 questions :
1. How can I use system.arraycopy to copy my two dimensional array? I have
searched but examples seem to be about one dim arrays.
2. How can I change the "static Object arrayGrow(Object a)" , to grow my two
dimensional array ?
3. If you know any codes or articles or java code regarding Cartesian
products , please tell me.
Thank you
Denis
There are unknown elements in your current code and your requiremen for
the application is also unclear. However, usage of System.arrayCopy()
is simple:
for (int i = 0; i < tempArray.length; ++i){
System.arrayCopy(solArray3[i], 0, tempArray[i], 0,
solArray3[i].length);
}
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