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c++pointersmatrixpointer-to-pointer

Dyanamic 2d array in C++ using double pointer


I have the following code, I made sure I did everything as explained in Pointer-to-pointer dynamic two-dimensional array

I need my 2d matrix to be dyanmic i.e the user needs to enter the dimensions. But I am getting error in my cin when taking the input form the user. whats wrong with the following code?

int numberOfRows, numberOfColumn;
cout << "Please enter the number of rows: ";
cin >> numberOfRows;
cout << endl << "Please enter the number of columns ";
cin >> numberOfColumn;


int** matrix= new int*[numberOfRows];

for (int i=0; i<numberOfRows; i++)
{
    matrix[numberOfRows]= new int[numberOfColumn];
}

for (int i=0; i<numberOfRows; i++)
{
    for(int j=0; j<numberOfColumn; j++)
    {
        cout << "Please enter Row " << (i+1) << " Column "<< (j+1) <<" element: ";
        cin>> matrix[i][j];
        cout << endl;
    }
}

for (int i=0; i<numberOfRows; i++)
{

    for(int j=0; j<numberOfColumn; j++)
    {
        cout << matrix[i][j];
    }
}

Solution

  • While allocating memory in for loop

    matrix[i]= new int[numberOfColumn]; 
         instead of matrix[numberOfRows]= new int[numberOfColumn];
    

    Note:you also need to free the allocated memory

    corrected code

    http://ideone.com/ILw1qa