Try to make larger array (dynamic array)

[cpcp]

I try to make "m" larger during the program is ran...
I try few things, but nothing works...

    #include <iostream>
    
    using std::cin;
    using std::cout;
    using std::endl;
    using std::nothrow;
    using std::cerr;
    
    int main()
    {
    	int n=3;
    	int **m;
    	//The initial array:
    	m=new (nothrow) int *[n];
    	for (int i=0;i<n;i++)
    	{
    		m[i]=new (nothrow) int[3];
    		m[i][0]=i+1;
    		m[i][1]=i+2;
    		m[i][2]=i+3;
    	}
    	for (int i=0;i<n;i++)
    				cout<<m[i][0]<<" "<<m[i][1]<<" "<<m[i][2]<<endl;
    	cout<<"----------------------------------------------\n";
    	int **t; //The temporary array:
    	t=new (nothrow) int *[n*2];
    	for (int i=0; i<n; i++)
    	{
    		t[i]=new int[3];
    		t[i+n]=new int[3];
    		t[i]=m[i];  //#####//
    		cout<<t[i][0]<<" @ "<<t[i][1]<<" @ "<<t[i][2]<<endl;
    	}
    	cout<<"\n\n\n";
    	for (int i=n; i<n*2; i++)
    	{
    		for (int j=0; j<n; j++)
    			t[i][j]=j+i;
    		cout<<t[i][0]<<" % "<<t[i][1]<<" % "<<t[i][2]<<endl;
    	}
    	cout<<"\n\n\n";
    	for (int i=0;i<n;i++)
    		delete []m[i];
    	delete []m;
    		m=t;  //#####//
    	
    	//Printing the final array:
    	for (int i=0;i<n*2;i++)
    		cout<<m[i][0]<<" "<<m[i][1]<<" "<<m[i][2]<<endl;
    
    	for (int i=0;i<n;i++)
    			delete []t[i];
    		delete []t;
    		return 0;
    }

Why I didn't get the array ?

here is the output:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

1 2 3 2 3 4 3 4 5

1 @ 2 @ 3 2 @ 3 @ 4 3 @ 4 @ 5 3 % 4 % 5 4 % 5 % 6 5 % 6 % 7 0 2 3 156127248 3 4 156127264 4 5 3 4 5 4 5 6 5 6 7

Can you find my error??
(look at the bold lines at the output...)

Thank you!!

[cpcp]

Someone??
Please...
I really need your help!!!

[D80DSL3A]

Your error is at line 31, which changes the assignments made on line 29.

[cpcp]

If I delete line 31, the first "m" array didn't copy:

This is what I got:
0 0 0
0 0 0
0 0 0
3 4 5
4 5 6
5 6 7

There should be:
1 2 3
2 3 4
3 4 5
(instead of the zeros).

Thank you!

[D80DSL3A]

Don't delete line 31. I thought you would realize the error once it was pointed out which line was wrong. Didn't you mean to copy the values stored in m[i][0], m[i][1] and m[i][2] instead?
t[i][0] = m[i][0]; t[i][1] = m[i][1]; t[i][2] = m[i][2];

[cpcp]

Yes, this is what I have to do...
line 31 don't do this?

Thank you!

[D80DSL3A]

You're welcome.

line 31 don't do this?

No. It does the same thing line 29 does. It assigns the pointers to point to some area of memory. This: t[i] = m[i]; makes the t[i] point to memory which is deleted on line 43.

[cpcp]

THANK YOU!!

so if I'm understanding you right,
I have to copy each item at the specific line?
e.g.:

for (int i=0; i<line_len; i++)
     t[3][i]=m[3][i];

(3 - is a specific line, it can be any other line...)

I'm right, yes?

Thank you again :-)

[D80DSL3A]

I think if you replace line 31 with:
t[i][0] = m[i][0]; t[i][1] = m[i][1]; t[i][2] = m[i][2];
your troubles will be gone.

[cpcp]

Thank you so much fun2code!!!
It's solve my problem!!! :-)