Access Violation writing location C++ 0x02D1F000 - arrays

Question

I'm attempting to initialize, populate and parse through an array in order to determine its "stability." To avoid a stack overflow, I decided to create dynamic arrays. The problem is that when it comes to populating the array, I get an exception regarding an access violation to a random location. I don't know if its something in the initialization or in the nested for loop when populating the array. I just can't seem to find anything wrong, nor my classmates/TAs. Thanks in advance for your help! I have tried compiling in VS, XCode, and g++ I have tried commenting out the dynamic array loops as well as the delete loops and gone for "regular arrays" such as float array[x][y] and I still get the same error.
#include <iostream>
#include <array>
#include <iomanip>
#include <cmath>
using namespace std;
int main() {
int check = 0;
int iteration = 0;
int newIteration = 0;
int newNewIteration = 0;
int const DIMENSION = 1024;
//Initializing the dynamic arrays in
//heap to avoid a stack overflow
float** firstGrid = new float*[DIMENSION];
for (int a = 0; a < DIMENSION; ++a) {
firstGrid[a] = new float[DIMENSION];
}
float** secondGrid = new float*[DIMENSION];
for (int b = 0; b < DIMENSION; ++b) {
secondGrid[b] = new float[DIMENSION];
}
float** thirdGrid = new float*[DIMENSION];
for (int c = 0; c < DIMENSION; ++c) {
thirdGrid[c] = new float[DIMENSION];
}
//Populating the arrays
//All points inside first array
for (int i = 0; i < DIMENSION; ++i) {
for (int j = 0; i < DIMENSION; ++j) {
firstGrid[i][j] = 0.0; //exception occurs here
}
}
for (int i = 1; i < DIMENSION - 1; ++i) {
for (int j = 1; i < DIMENSION - 1; ++j) {
firstGrid[i][j] = 50.0;
}
}
//Pre-setting second array
for (int i = 0; i < DIMENSION; ++i) {
for (int j = 0; i < DIMENSION; ++j) {
secondGrid[i][j] = 0.0;
}
}
for (int i = 1; i < DIMENSION - 1; ++i) {
for (int j = 1; i < DIMENSION - 1; ++j) {
secondGrid[i][j] = 50.0;
}
}
//Pre-setting third array
for (int i = 0; i < DIMENSION; ++i) {
for (int j = 0; i < DIMENSION; ++j) {
thirdGrid[i][j] = 0.0;
}
}
for (int i = 1; i < DIMENSION - 1; ++i) {
for (int j = 1; i < DIMENSION - 1; ++j) {
thirdGrid[i][j] = 50.0;
}
}
//Checking and Populating new arrays
for (int p = 1; p < DIMENSION - 1; ++p) {
for (int q = 1; q < DIMENSION - 1; ++p) {
check = abs((firstGrid[p - 1][q] + firstGrid[p][q - 1] + firstGrid[p + 1][q] + firstGrid[p][q + 1]) / 4
- firstGrid[p][q]);
if (check > 0.1) {
secondGrid[p][q] = (firstGrid[p - 1][q] + firstGrid[p][q - 1] + firstGrid[p + 1][q] + firstGrid[p][q + 1]) / 4;
iteration = iteration + 1;
}
}
}
for (int p = 1; p < DIMENSION - 1; ++p) {
for (int q = 1; q < DIMENSION - 1; ++p) {
check = abs((secondGrid[p - 1][q] + secondGrid[p][q - 1] + secondGrid[p + 1][q] + secondGrid[p][q + 1]) / 4
- secondGrid[p][q]);
if (check > 0.1) {
thirdGrid[p][q] = (secondGrid[p - 1][q] + secondGrid[p][q - 1] + secondGrid[p + 1][q] + secondGrid[p][q + 1]) / 4;
newIteration = newIteration + 1;
}
}
}
for (int p = 1; p < DIMENSION - 1; ++p) {
for (int q = 1; q < DIMENSION - 1; ++p) {
check = abs((thirdGrid[p - 1][q] + thirdGrid[p][q - 1] + thirdGrid[p + 1][q] + thirdGrid[p][q + 1]) / 4
- thirdGrid[p][q]);
if (check > 0.1) {
newNewIteration = newNewIteration + 1;
}
}
}
//Deleting arrays and freeing memory
for (int x = 0; x < DIMENSION; ++x) {
delete [] firstGrid[x];
}
delete [] firstGrid;
for (int x = 0; x < DIMENSION; ++x) {
delete [] secondGrid[x];
}
delete [] secondGrid;
for (int x = 0; x < DIMENSION; ++x) {
delete [] thirdGrid[x];
}
delete [] thirdGrid;
//iteration checking
cout << iteration << endl << newIteration << endl << newNewIteration;
if (iteration == 179 || newIteration == 179 || newNewIteration == 179) {
return 0;
}
else {
return 1;
}
}

Answer 1

You should use j consistently in your second for-loop (where the error occurs):
for(j=0; j < DIMENSION; j++)