Thread: Dynamc Memory

I need to declare a bidimensional arrey but using dynamic memory. (C++)

I used:

int x,y;
cin>>x;
cin>>y;
int **m=new[x][y];

ERROR: Parse error before '['

I also used:

int **m= new int[x][y];

ERROR: Assigment to 'int **' from 'int (*)[((y-1)+1)]'

please help me...

Well, what you're REALLY doing is making an array of arrays.

So, do this:

Code:

int ** m;
m = new int * [x];
for (int i = 0; i < x; i++){
	m[i] = new int[y];
}

//Now, you can use the array.

//To deallocate, deallocate in reverse order you allocated:

for (int i = 0; i < x; i++){
	delete[] m[i];
}
delete[] m;

Thnks a lot you've saved my life...

Not as eloquent as the first but a bit more efficient.

Code:

#include "stdafx.h"
#include <iostream>
using namespace std;

int main(int argc, char* argv[])
{
	int x, y;
	cout << "Enter number of arrays: " << flush;
	cin >> x;
	
	cout << "Enter the number in each array : " << flush;
	cin >> y;

	int * pArry = new int[ x * y ];

	if( !pArry )
		throw bad_alloc( );

	for ( int i = 0; i < x; i++ )
	{
		for( int j = 0; j < y; j++ )
		{
			(pArry + i)[ j ] = j + i;
		}
	}


	for ( i = x - 1; 0 <= i; i-- )
	{
		for( int j = y - 1; 0 <= j; j-- )
		{
			cout << "   j = " << j << "  i = " << i << "  j + i  =  pArry[i][j] = " << (pArry + i )[ j ] << endl;
		}
	}

	delete pArry[];

	return 0;
}