Solved

Unhandled exception at 0x012510ab in Sim HW5.exe: 0xC0000005: Access violation writing location 0x00000000.

Posted on 2008-10-20
1
679 Views
Last Modified: 2012-05-05
Code runs fine for awhile and then breaks in first "for" loop at random points between Counter2 = 150 and 450 and throws the error:

Unhandled exception at 0x009810ab in Sim HW5.exe: 0xC0000005: Access violation writing location 0x00000000.

Any ideas why?
// Sim HW5.cpp : Defines the entry point for the console application.
//
 
#include "stdafx.h"
#include <iostream>
#include <vector>
#include <cmath>
 
using namespace std;
 
int _tmain(int argc, _TCHAR* argv[])
{
	int Counter = 0;
	int Counter2;
	int Counter3;
 
	int n = 100000;
	
	int fj[20] = {0};
	
	double Divisor;
	double Z0 = 1;
	double Zi;
	double ZiMinusOne;
	double Ui;
	double TwoPowerThirtyOne;
	TwoPowerThirtyOne = pow((double)2,31);
	double v[100000];
 
	while (Counter < n+1){
		if (Counter == 0)
			ZiMinusOne = Z0;
		else
			ZiMinusOne = Zi;
 
		Divisor = (floor( 16807*ZiMinusOne/(TwoPowerThirtyOne-1)));
		Zi = 16807*ZiMinusOne - (Divisor) * (TwoPowerThirtyOne-1);
 
		Ui = Zi/(TwoPowerThirtyOne-1);
 
		v[Counter] = Zi;
 
		Counter++;
		}
 
 
breaks-->	for (Counter2 = 0; Counter2 < n-1; Counter2++){
		for (Counter3 = 0; Counter3 < 20; Counter3++){
			if (v[Counter2] >= Counter3*TwoPowerThirtyOne/20 && v[Counter2] <= (Counter3+1)*TwoPowerThirtyOne/20)
				fj[Counter2]++;
		}
	}
 
	for (Counter2 = 0; Counter2 < n-1; Counter2++)
		cout << "fj" << Counter2 << ": " << fj[Counter2] << endl;
 
	system ("PAUSE");
}

Open in new window

0
Comment
Question by:ltdanp22
1 Comment
 
LVL 86

Accepted Solution

by:
jkr earned 500 total points
ID: 22758670
Well, the above is running fine here (compiles with VC8). You might want to initialize each and every variable thoroughly though, e.g.
int _tmain(int argc, _TCHAR* argv[])
{
        int Counter = 0;
        int Counter2 = 0; // <--
        int Counter3 = 0; // <--
 
        int n = 100000;
        
        int fj[20] = {0};
        memset(fj,0,20 * sizeof(int)); // <--
        
        double Divisor = 1.0; // <--
        double Z0 = 1;
        double Zi = 0.0; // <--
        double ZiMinusOne = 0.0; // <--
        double Ui = 0.0; // <--
        double TwoPowerThirtyOne = 0.0; // <--
        TwoPowerThirtyOne = pow((double)2,31);
        double v[100000];
        memset(v,0,100000 * sizeof(double)); // <--
 
        while (Counter < n+1){
                if (Counter == 0)
                        ZiMinusOne = Z0;
                else
                        ZiMinusOne = Zi;
 
                Divisor = (floor( 16807*ZiMinusOne/(TwoPowerThirtyOne-1)));
                Zi = 16807*ZiMinusOne - (Divisor) * (TwoPowerThirtyOne-1);
 
                Ui = Zi/(TwoPowerThirtyOne-1);
 
                v[Counter] = Zi;
 
                Counter++;
                }
 
 
                for (Counter2 = 0; Counter2 < n-1; Counter2++){
                for (Counter3 = 0; Counter3 < 20; Counter3++){
                        if (v[Counter2] >= Counter3*TwoPowerThirtyOne/20 && v[Counter2] <= (Counter3+1)*TwoPowerThirtyOne/20)
                                fj[Counter2]++;
                }
        }
 
        for (Counter2 = 0; Counter2 < n-1; Counter2++)
                cout << "fj" << Counter2 << ": " << fj[Counter2] << endl;
 
        system ("PAUSE");
}

Open in new window

0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This tutorial is posted by Aaron Wojnowski, administrator at SDKExpert.net.  To view more iPhone tutorials, visit www.sdkexpert.net. This is a very simple tutorial on finding the user's current location easily. In this tutorial, you will learn ho…
Examines three attack vectors, specifically, the different types of malware used in malicious attacks, web application attacks, and finally, network based attacks.  Concludes by examining the means of securing and protecting critical systems and inf…
The goal of this video is to provide viewers with basic examples to understand how to use strings and some functions related to them in the C programming language.
The goal of this video is to provide viewers with basic examples to understand how to create, access, and change arrays in the C programming language.

816 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now