Matrices dinamicas v1

#include<iostream>
#include<string>
#include<time.h>
using namespace std;
using namespace System;

void crearMatriz(float **&M, int cf, int cc)
{
    M = new float*[cf];
    for (int i = 0; i <cf; i++)
    {
        M[i] = new float[cc];
    }
}
void liberaMatriz(float **M, int cf)
{
    for (int i = 0; i < cf; i++)
    {
        delete[] M[i];
    }
    delete[] M;
}

void cargaMatriz(float **M, int cf, int cc)
{
    srand(time(NULL));
    for (int i = 0; i < cf; i++)
    {
        for (int j = 0; j < cc; j++)
        {
            M[i][j] = float(rand() % (21));
        }
    }
}
void mostrarDatos(float **M, int cf, int cc)
{
    for (int i = 0; i < cf; i++)
    {
        for (int j = 0; j < cc; j++)
        {
            cout<<M[i][j]<<"\t";
        }
        cout << endl;
    }
}

float hallarPromedio(float **M, int cf, int cc)
{
    float P3 = 0;
    for (int i = 0; i < 30; i++)
    {
        P3 += M[i][2];
    }
    return P3/30;
}
void main()
{
    int cf = 30, cc = 6;
    float **notas;
    crearMatriz(notas, cf, cc);
    cargaMatriz(notas, cf, cc);
    mostrarDatos(notas, cf, cc);
    cout << "Promedio de practica 3: " << hallarPromedio(notas, cf, cc) << endl;
    liberaMatriz(notas, cf);
    system("pause>NULL");
}