Help with some c++ runtime errors

[hobosrock696]

I wrote some code and so far all it should do is allocate memory and then free it up however if I try to allocate A LOT of memory it doesn't throw an error instead it just locks up....

Now the program will accept 999999999 and throw the error I coded in but if you try adding 1 more 9 so there are 10 digits it freezes up and does not throw an error. The last message on the screen when it freezes is

"Allocating memory for operation, please wait..."

So I would think it literally freezes outside of my code in one of the defines?

#include "stdafx.h"
#include <iostream>
#include <sstream>
#include <string>
#include <new>
using namespace std;



int* makelist (int a)
{
     cout << "Initializing memory for operation, please wait... \n";
     int * lenghth;
     lenghth = new (nothrow) int [a];
     if (lenghth == 0)
     {
          cout << "ERROR ALLOCATING MEMORY!\n";
          return 0;
     }
     cout << "Done!\n";
     return(lenghth);
}



void clearmem (int * addy, int lenghth)
{
     cout << "Freeing memory please wait...\n";
     delete[lenghth] addy;
     cout << "Done!";
}



void pause()
{
     cin.ignore();
     cin.get();
}



int main()
{
	int a;
	int a_const;
	int * list_location;
	cout << "Enter the number of numbers you want to find in the Fibonaci sequence.\n";
	cin >> a;
	a_const = a;
	if (a == 0)
	{
		cout << "Ummmm so you started this program to not use it.... im not going\nto calculate the 0th number -.-\npress enter to close...";
		pause();
		return 0;
	}
	list_location = makelist (a);
	clearmem(list_location, a_const);
	pause();
	return 0;
}