System.arraycopy (2 dim array) and growth of 2 dim array

[Denis Palas]

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[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[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

 

[hiwa]

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[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[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, 0, tempArray, 0,
solArray3.length);
}