Question

I am practicing how to create a 2D array and shrink it.
This is my function:

void Resize(int rownums,int columnnums)
{
    MyMatrix newM(rownums,columnnums);
    for(int i=0;i<rownums;i++)
        for(int j=0;j<columnnums;j++)
            newM.table[i][j]=table[i][j];

    for(int i=0;i<rows;i++)
    for(int j=0;j<columns;j++)
    delete []table[j];

    delete[]table;
    rows=newM.rows;
    columns=newM.columns;
    table=new string*[rows];
    for(int i=0;i<rows;i++)
        table[i]=new string[columns];

    for(int i=0;i<rows;i++)
        for(int j=0;j<columns;j++)
            table[i][j]=newM.table[i][j];
}

The problem is that it gives me a debug assertion failed.
I don’t understand what I did wrong or how I can fix it!!!
Anything you have in mind can help me!!
thank you

Answer 1

This is incorrect:

for(int i=0;i<rows;i++)
for(int j=0;j<columns;j++)
delete []table[j];

You don’t need the outer loop as it causes deletion of already deleted arrays, leading to undefined behavior.