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;
}

[AeroMan]

im not sure, but try add add System("PAUSE");
but you did not add "Clearmem" & Pause into your main functions, try to add that.
im not a pro, dont be angry if its uncorrect, i just try

[hobosrock696]

Im not sure what your saying exactly but I do hoave the two functions used in main I know that it freezes in the makelist function and I tried to avoid using System("pause") because I want to keep it as easy to compile on multiple platforms as possible. Please do elaborate if I misunderstood and ANY help is welcome

EDIT: I tried to throw in a pause directly after the cout command that displays the last text on screen and strangely it skips this pause command and any other pause I put in anywhere be it the pause function I wrote or system("pause")

[hobosrock696]

Bump, dont want to start a new thread :/ sorry

[Toxic Waltz]

this is a guess...

INT_MIN


Minimum value for a variable of type int.


–2147483648

INT_MAX


Maximum value for a variable of type int.


2147483647


999999999 is smaller than int max
9999999999 is larger than int max and give an error.

try the values 214783647 and 214783648
if I'm right the last one gives an error.

is it bigger than or bigger then?

[hobosrock696]

See theres the funny thing... neither give an error.... both freeze so what Im going to try is getting an input as a string and pulling the number out into a variable.... Will post back and thanks for the attempt anything it welcome


EDIT: So it turns out that using stringstream(stringvar) >> integervar DOES NOT help.... hmm... time to get sidetracked and write code to check for integers in a string.....

EDIT 2: So even at 1 billion it throws an error but at a certain point it just freaks and freezes..... Otherwise it will throw an error.... anyone ever done this? allowed the user to allocate a bunch of memory based on a number they put in? Im definitely missing something....