Hi, when i compile my code i get this error : "error : variable-sized object 'largeArray2' may not be initialized"

I just don't understand this error, any help would be appreciated, thanks in advance.

Code:

float give_coefficients_routh_table_and_fill_two_first_lines(int denominator_degree)
{
float largeArray2[20][20] = {0};
int l = 0;
int c = 0;
int e = denominator_degree ;
for ( e = denominator_degree; e>=0; e--)
{
float array_of_coefficients[20];
float d(e);
cout << "what is the coefficient linked with degree" << e << "?" << endl;
cin >> d;
d = array_of_coefficients[e];
if ( l==2 ){ l = 0; c++;}
float largeArray2[l][c] = {d};
l++;
}
return largeArray2[20][20];
}