模块“Project6.exe”中地址 XXXXXXXX 处的错误访问冲突

在 c++ builder 10.3 类中

class Matrix
{
    int **m;
    int r,s;
public:
    Matrix(){}
    Matrix(int st,int rd)
    {
        r = rd;
        s = st;
        *m = new int [s];
    for(int i=0; i<s; i++)
    {
        m[i] = new int [r];
        for(int j=0; j<r; j++)
        {
            m[i][j] = 0;
        }
    }

    }
    ~Matrix()
    {
        for(int i=0; i<s; i++)
        delete [] m[i];
        delete [] m;
    }
     void CreateMatrix(int st,int rd, int ch)
    {
        //m[st][rd] = ch;
    }

};

Matrix matr;
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm5 *Form5;
__fastcall TForm5::TForm5(TComponent* Owner)
    : TForm(Owner)
{
}
void __fastcall TForm5::Button1Click(TObject *Sender)
{
    if(Edit1->Text == "" || Edit2->Text == "") ShowMessage("Заповніть поля" );
    else
    {
        if(StrToInt(Edit2->Text)<1 || StrToInt(Edit1->Text)<1) ShowMessage("Розмір матриці повинен бути більше 0" );
        else
        {
            StringGrid1->Visible = true;
            StringGrid1->RowCount = StrToInt(Edit2->Text);
            StringGrid1->ColCount = StrToInt(Edit1->Text);
            Matrix matr(StrToInt(Edit1->Text),StrToInt(Edit2->Text));
        }
    }
}
void __fastcall TForm5::Button2Click(TObject *Sender)
{
    for(int i=0; i<StrToInt(Edit1->Text); i++)
    {
        for(int j=0; j<StrToInt(Edit2->Text); j++)
        {
              matr.CreateMatrix(i,j,StrToInt(StringGrid1->Cells[j][i] ));
        }
    }
}