Addition of polynomials with different grade - c++

Question

I'm currently writing a code that sums together the coefficient of two polynomials.
This all works fine as long as the grade of the first polynomial is smaller or equal to the second. "if (d1 <= d2)"
However, when "d1 > d2", the code seems to have some kind of issue I don't understand.
I'm sitting on this for a while now but don't seem to find the problem. Does anybody have any hints?
Thanks in advance.
#include <iostream>
#include <math.h>
using namespace std;
double * poli_sum (double * p1, int d1, double * p2, int d2, int & dr);
double * read_poly(int &n){
cout << "Grade of function: ";
cin >> n;
double * c=new double[n+1];
for(int i=0;i<=n;i++){
cout << "Coefficient of degree " << i << ": ";
cin >> c[i];
}
return c;
}
double * read_second_poly(int &m){
cout << "Grade of second function: ";
cin >> m;
double * g=new double[m+1];
for(int i=0;i<=m;i++){
cout << "Coefficient of degree " << i << ": ";
cin >> g[i];
}
return g;
}
double * poli_sum (double * p1, int d1, double * p2, int d2, int & dr){
dr = 0;
if (d1 <= d2){
cout << "You're in first, d1 = " << d1 << endl;
cout << "d2 = " << d2 << endl <<endl;
for (int i = 0; i <= d2; i++){
if (i >d1) p1[i] = 0; // setting array[i] to zero when it gets outside the defined grade
cout << (p1[i]+p2[i])<< endl;
cout << "pi1( "<< i << "): "<< p1[i] << endl;
cout << "pi2( "<< i << "): "<< p2[i] << endl << endl;
dr++;
}
}
else if (d1 > d2){
cout << "You're in second, d1 = " << d1 << endl;
cout << "d2 = " << d2 << endl <<endl;
for (int i = 0; i <= d1; i++){
if (i > d2) p2[i] = 0; // setting array[i] to zero when it gets outside the defined grade
cout << (p1[i]+p2[i])<< endl;
cout << "pi1( "<< i << "): "<< p1[i] << endl;
cout << "pi2( "<< i << "): "<< p2[i] << endl << endl;
dr++;
}
}
cout << "dr: "<< dr << endl;
return 0;
}
int main()
{
double *p1;
double *p2;
int g1, g2, g3;
p1=read_poly(g1);
p2 = read_second_poly(g2);
poli_sum(p1,g1, p2, g2, g3);
delete[] p1;
delete[] p2;
return 0;
}