Thread: Help me with code conversion

Hello!

Could anybody help me with conversioning c++ code to java...I'm having a very hard time with pointers and memory allocations (memcpy) written in c++, which I want to write in java.I would be very grateful, if somebody took a couple of minutes and help me to fix this problem, which is bothering me for days.

Here's the code:

#include<iostream>
using namespace std;

class CMO
{

private:

int m_cnt;


public:
/* Constructor/Destructor */

CMO(int in[], int cnt)
{
m_in = new int[cnt];
m_cnt = cnt;

for(int i=0;i<m_cnt;i++)
{
m_in[i]=in[i];
}
}


int Sort()
{
return mSort(0, m_cnt);
}

private:
int mSort(int ind, int cnt)
{
int tmp;
int left, right;

if (cnt == 1) {
return 0;
}

left = (cnt + 1) / 2;
right = cnt / 2;

if (cnt == 2) {
mDisplay(ind, 1, 1);

if (m_in[ind] > m_in[ind+1]) {
tmp = m_in[ind];
m_in[ind] = m_in[ind+1];
m_in[ind+1] = tmp;
}

mDisplay(ind, 2, 0);

} else {
mDisplay(ind, left, right);

mSort(ind, left);
mSort(ind+left, right);

mOrder(ind, left, right);

mDisplay(ind, left + right, 0);
}

return 0;
}

int mOrder(int ind, int left, int right)
{
int i, a, b;
int *tmp;

tmp = new int[left+right];
a = b = 0;

for (i = 0; i < (left+right); ++i) {
if ((m_in[ind+a] > m_in[ind+left+b] && b < right) || a >= left) {
tmp[i] = m_in[ind+left+b];
++b;
} else if (a < left) {
tmp[i] = m_in[ind+a];
++a;
}
}

memcpy(&m_in[ind], tmp, (left + right) * sizeof(int));





delete [] tmp;

return 0;
}


void mDisplay(int ind, int left, int right)
{
int i, j;

for (i = 0; i < left; ++i) {
std::cout << m_in[ind+i] << " ";
}

if (right == 0) {
std::cout << std::endl;
return;
}

std::cout << "| ";

for (j = 0; j < right; ++j) {
std::cout << m_in[ind+i+j] << " ";
}
std::cout << std::endl;
}


};


int main(int argc, char *argv[])
{
int in[] = {8, 5, 6, 1, 7, 2, 0, 9};

CMO cmo(in,8);

cmo.Sort();

system("PAUSE");
return 0;
}

Begin with the code are trying to convert. (Ie, put Java aside temporarily to make the problem more tractable). The aim is understand what the code is doing. Then you will have something specific to implement in Java.

A convenient way to express the behavior of the C++ code is to add comments before each method, saying what that method does. Pay attention to what each argument represents, to what is meant by any returned value, and to the side effects of the method (including what it might print).

---

If the conversion is not the task you are trying to do - that is, if you are trying to do something and have come to believe that the C++ code is doing that thing - consider that that the attempt to convert the code may be a distraction. Especially if you are unfamiliar with the language the approach outlined above may involve you in more work than simply writing the Java code.

Hello, thank you for replying me quickly.

I'm trying to get a substitute code done by pointers in c++ (which explicitly don't exist in java), by equivalent (non-pointer) code in java.