Dynamic matrix in C++ - c++

Question

I am working with a multidimensional array but i get an exception, i have searched a lot but i find the same answer i'm using, the exception jumps when i try to allocate matriz[i] = new double[n]. I have tried both the commented and uncommented solutions with no luck.
void interpol(double *arr_x, double *arr_y, int n, double *results) {
//double** matriz = new double*[n];
double** matriz;
matriz = (double**) malloc(n * sizeof(double*));
for(int i = 0; i < n; i++){
//matriz[i] = new double[n+1];
matriz[i] = (double*) malloc(n+1 * sizeof(double));
for(int j = 0; j < n; j++) {
matriz[i][j] = pow(arr_x[i],j);
}
matriz[i][n] = arr_y[i];
}
gaussiana(matriz, n, results);
}
--- EDIT---
The function gaussiana is working fine, since i have tested outside this function. The exception is thrown in either:
//matriz[i] = new double[n];
matriz[i] = (double*) malloc(n * sizeof(double));
n is never more than 10.
The exception thrown is:
First-chance exception at 0x00071c4d in Interpolacion.exe: 0xC0000005:
Access violation reading location 0x00000000.
Unhandled exception at 0x774b15de in Interpolacion.exe: 0xC0000005: Access violation reading location 0x00000000.
The program '[8012] Interpolacion.exe: Native' has exited with code -1073741819 (0xc0000005).
----EDIT----
I finally got it working, the issue was not in matriz, but with arr_x/arr_y, the external routine was sending the data wrong (oddly the error and the stacktrace always referred me to the new double[n] assignation)

Answer 1

If you want to use the std::vector route, you can use something like below (untested, shown just as a guide). Keep in mind that std::vector<std::vector<double> > is not compatible with double **, so your gaussiana function might need to be rewritten to accept the new type.:
// Include the header!
#include <vector>
// Be careful about the use of "using namespace std", I'm only using it here
// because it's a small example
using namespace std;
vector<vector<double> > matriz;
for (int i = 0; i < n; i++)
{
// Create a new vector "v" with n+1 elements
vector<double> v(n + 1);
// fill this vector
for (int j = 0; j < n; j++)
v[j] = pow(arr_x[i], j);
v[n] = arr_y[i];
// add it to the matrix
matriz.push_back(v);
}

Answer 2

I don't see anything in the code present which would cause an exception. It must be gaussiana() causing the trouble. Try commenting that line out and see if the program still faults.
It would be useful to know the range of n. As long as it is relatively small (< 1000) on modern 32- or 64-bit machines, malloc() should not fail. However, if the program runs with restricted memory, or n is large, it is likely that some mallocs would fail. Since there is no checking for NULL being returned, the program would indicate trouble by SEGFAULTing when trying to dereference the pointer.
If the function is called multiple times, the memory leaking could add up to a significant heap shortage and induce malloc() to fail.