Heap Corruption detected: after Normal block(#176) - c++

Question

So I got this introduction to Programming assignment, I have to write a program that find the nth member of the following sequence 1, 121, 1213121, 121312141213121.. and so on. Basically, the first member is 1, and every next one is made of [the previous member] [n] [the previous member]. N < 10. So I got this problem that I do not understand, tried searching for it in the internet but didn't get anything that can help me.
#include "stdafx.h"
#include <iostream>
using namespace std;
int size(int n, int realsize);
int main()
{
int n;
cin >> n;
if (n == 1) {
cout << "1";
return 0;
}
int helper = 0;
char c = '2';
char* look;
char* say;
say = new char[size(n, 1) + 1]();
look = new char[size(n - 1, 1) + 1]();
look[0] = '1';
while (helper < n) {
for (int i = 0; i < size(helper + 1, 1); i++) {
say[i] = look[i];
}
say[size(helper + 1, 1)] = c;
for (int i = size(helper + 1, 1) + 1; i < size(helper + 1, 1) * 2 + 1; i++) {
say[i] = look[i - (size(helper + 1, 1) + 1)];
}
for (int i = 0; i < size(helper + 1, 1) * 2 + 1; i++) {
look[i] = say[i];
}
helper += 1;
}
cout << say;
delete[] say;
delete[] look;
return 0;
}
int size(int n, int realsize)
{
if (n == 1)
return realsize;
else
return size(n - 1, realsize * 2 + 1);
}

Answer 1

You are overwriting the capacity of your look variable. It ends out being written with the entire contents of say, so it needs to have that same size as well.
While I don't condone the below code as good code, it has minimal adjustments from your own implementation and should give a more solid base to continue towards a working outcome. I tested it with the first couple of numbers, but that's no guarantee it is perfect.
#include <iostream>
using namespace std;
int size(int n, int realsize);
int main()
{
int n;
cin >> n;
if (n == 1)
{
cout << "1";
return 0;
}
int helper = 0;
char c = '2';
char * look;
char * say;
say = new char[size(n, 1) + 1]; // Ditch the () call, which is confusing.
look = new char[size(n, 1) + 1]; // Make the same size as "say"
look[0] = '1';
while (helper < n - 1) // You're overrunning this loop I think, so I did it to n - 1.
{
for (int i = 0; i < size(helper + 1, 1); i++)
{
say[i] = look[i];
}
say[size(helper + 1, 1)] = c + helper; // You were adding '2' every time, so this will add 2, 3, 4, etc incrementally.
for (int i = size(helper + 1, 1) + 1; i < size(helper + 1, 1) * 2 + 1; i++)
{
say[i] = look[i - (size(helper + 1, 1) + 1)];
}
for (int i = 0; i < size(helper + 1, 1) * 2 + 1; i++)
{
look[i] = say[i];
}
helper += 1;
}
say[size(n, 1)] = '\0'; // Null-terminate "say" before printing it out.
cout << say;
delete[] say;
delete[] look;
return 0;
}
int size(int n, int realsize)
{
if (n == 1)
return realsize;
else
return size(n - 1, realsize * 2 + 1);
}