Dynamic 2D Arrays -- C++

[JogaBonito1502]

Here's my problem:

I'm creating a program that will encrypt and decrypt files by arranging the content in square matrix and doing various transformations to it. I'm currently writing the header file that will contain a class with functions in it. Each function will represent a step in the encryption/decryption of the file.

My first function is very simple. It simply reads the contents of the file and decides what dimensions the square array should be.

int IndentifyMatrix();

This function will return the size of the m x m matrix.

My next function will change the characters into their respective ASCII values, and will sort them into the m x m matrix. In this definition, I need my dimensions to be left open (dynamic) because the dimensions will be sent in a variable pointer which contains the result of the function above. This is what my declaration looks like:

void Encrypt(int* MatrixSize, char const* (*inFile), int CypherMatrix[][]);

Here, I have two questions:

1. inFile needs to be a 2D array containing the characters of the text file in a M x M array (where M = the size of the matrix defined by the IdentifyMatrix()).

I could make this array 1D, but if I do so, I want to load the contents of the text file into the program and make this 1D array a pointer.

I also want the values of this 2D (or 1D pointer) array to be constants (so they can't be toyed with while the program runs).

2. CypherMatrix needs to be a dynamic array (one without the dimensions defined) until I run IdentifyMatrix(). As stated earlier, IdentifyMatrix() will return me a value with the dimensions of the square matrix. How do I declare this dynamic 2D array (this NEEDS to be 2D so I can do matrix transformations).

Thanks for the help.