How do I create my 2D table?

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Hi, I'm doing a BubbleShot project and I hae to create a 15*18 table to sort my bubbles, I have to use pointers but I'm not goot to this, I try to initialise it but I have a buffer overflow that I can solve, here is my .h

C++

#pragma once
class CPlateau
{
public:
	CPlateau();
	~CPlateau();
	int **table;
	void Init();
};

and here is my .cpp

C++

#include "pch.h"
#include "CPlateau.h"
CPlateau::CPlateau()
{
	table = new int* [18];
	for (int i = 0; i < 18; i++)
	{
		table[i] = new int[15];
	}
	
	for (int i = 0; i < 15; i++)
		{
			table[i][17] = 10 + i % 2;
		}
}
CPlateau::~CPlateau()
{
	for (int i = 0; i < 15; i++)
		delete[] table[i];
	delete[] table;
}
void CPlateau::Init()
{
	for (int i = 0; i < 17; i++)
		for (int j = 0; j < 9; j++)
			table[i][j] = rand() % 6 + 1;


}

What I have tried:

I tried to use malloc and calloc but it get worst and I don't know what to change

Posted 21-Jan-21 21:46pm

Axel Patron

Updated 21-Jan-21 22:11pm

CPallini

v2

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OriginalGriff · Answer 1 · 2021-01-21T22:04:00

Look at your code:

C++

table = new int* [18];
for (int i = 0; i < 18; i++)
{
	table[i] = new int[15];
}

for (int i = 0; i < 15; i++)
	{
		table[i][17] = 10 + i % 2;
	}

Look at it closely, and see what you are doing:

C++

table = new int* [18];

You create an array of 18 pointers to integers: that's one dimension.

C++

for (int i = 0; i < 18; i++)
{
	table[i] = new int[15];
}

You fill in each pointer with an array of 15 integers.

C++

for (int i = 0; i < 15; i++)
	{
		table[i][17] = 10 + i % 2;
	}

You go through the first 15 elements of the outer array, trying to set element 17 of the inner array (which contains 15 elements) to a value ...

If you want to create a 18 * 15 jagged array and fill it, use a nested loop:

C++

int** table = new int*[18];
int x = 0;
for (int i = 0; i < 18; i++)
    {
    table[i] = new int[15];
    for (int j = 0; j < 15; j++)
        {
        table [i][j] = x++;
        }
    }