Recursive function throws unhandled exception at 0x79B20AD2 (ucrtbased.dll) - c++

Question

I write minesweeper and the current task is to write a function that would uncover the areas that have no mines neighbouring to them. In the original minesweeper if you click within the area with no mines, it would open up an area until there are mines alongside its borders. For that I wrote the function unravel(). Here is the code:
#include <iostream>
#include <cstdlib>
#include <time.h>
#include <vector>
#include <string>
using namespace std;
#define Str1D vector<string>
#define Str2D vector<Str1D>
#define Int1D vector<int>
#define Int2D vector<Int1D>
void unravel(Str2D &fogofwar, Int2D &display, int x, int y) {
for (int minusrows = -1; minusrows < 2; minusrows++){ // going through the
// neighbouring cells (+ the cell itself)
for (int minuscolumns = -1; minuscolumns < 2; minuscolumns++){
if (x + minusrows > 0 && y + minuscolumns > 0 && x + minusrows < fogofwar.size() && y + minuscolumns < fogofwar[0].size()){ // checking
// if within borders
if (x > 0 && y > 0 && x < fogofwar.size() && y < fogofwar[0].size()) { // checking if the oririginal
// values are within borders
fogofwar[x + minusrows][y + minuscolumns] = to_string(display[x + minusrows][y + minuscolumns]); // revealing the
// neighbouring cells
if (display[x + minusrows][y + minuscolumns] == 0) { // if the cell is 0 on the display,
// open it and the 8 neighbouring to it cells
if (not (minusrows == 0 && minuscolumns == 0)) { // if it's not the same cell, of course,
// otherwise it's an endless cycle
unravel(fogofwar, display, x + minusrows, y + minuscolumns);
}
}
}
}
}
}
}
int main() {
int row, column, prob;
bool running = true;
cout << "Input width and height: ";
cin >> row >> column;
cout << endl << "Input mines probability (%): ";
cin >> prob;
cout << endl;
srand (time(NULL));
Int2D field(row + 1, Int1D(column + 1));
Int2D display(row + 1, Int1D(column + 1));
Str2D fogofwar(row + 1, Str1D(column + 1, "*"));
field[0][0] = 0; // field of mines
display[0][0] = 0; // display of neighbouring mines
fogofwar[0][0] = to_string(0); // what the player will see
for (int i = 1; i < row + 1; i++) { //assigning coordinates
field[i][0] = i;
display[i][0] = i;
fogofwar[i][0] = to_string(i);
}
for (int j = 1; j < column + 1; j++) { //assigning coordinates
field[0][j] = j;
display[0][j] = j;
fogofwar[0][j] = to_string(j);
}
for (int i = 1; i < row + 1; i++){ // filling the field with mines
for (int j = 1; j < column + 1; j++){
int x = rand() % 100;
if (x < prob) {
field[i][j] = 1;
}
else{
field[i][j] = 0;
}
}
}
cout << endl << endl;
for (int i = 0; i < row + 1; i++){ // printing field
for (int j = 0; j < column + 1; j++){
cout << " " << field[i][j] << " ";
}
cout << endl;
}
cout << endl << endl;
for (int i = 0; i < row + 1; i++){ // assigning the display of amount of neighbouring mines
for (int j = 0; j < column + 1; j++){
int count = 0;
if (i > 0 && j > 0){
for (int minusrows = -1; minusrows < 2; minusrows++){
for (int minuscolumns = -1; minuscolumns < 2; minuscolumns++){
if (i + minusrows > 0 && i + minusrows < row + 1 && j + minuscolumns > 0 && j + minuscolumns < column + 1){
if (field[i + minusrows][j + minuscolumns] == 1){
count++;
}
}
}
}
display[i][j] = count;
}
cout << " " << display[i][j] << " ";
}
cout << endl;
}
cout << endl << endl;
while (running) {
for (int i = 0; i < row + 1; i++){
for (int j = 0; j < column + 1; j++){
cout << " " << fogofwar[i][j] << " ";
}
cout << endl;
}
cout << endl;
int x, y;
cout << endl << "Input the target cell (x, y): ";
cin >> x >> y;
cout << endl;
unravel(fogofwar, display, x, y);
}
return 0;
}
If I delete the recursivity by changing unravel(fogofwar, display, x + minusrows, y + minuscolumns); to continue; within the function unravel(), it works as intended. But I need to open up the entire area where there are 0's on the display. Any way to skirt the error or fix it for good?

Answer 1

First of all, I am unable to reproduce the error with the information in question. Please try to specify the complete usecase along with what values you are getting into error with.
However, there is an obvious problem in the implementation of unravel.
You go over the same cell multiple times, until the memory exceeds total memory of course (I believe this is the point your program crashes)
You should maintain the slots already visited. You can do this in multiple ways. I am providing one of the ways to handle this.
Try the following code:-
#include <iostream>
#include <cstdlib>
#include <time.h>
#include <vector>
#include <string>
using namespace std;
#define Str1D vector<string>
#define Str2D vector<Str1D>
#define Int1D vector<int>
#define Int2D vector<Int1D>
void unravel(Str2D &fogofwar, Int2D &display, int x, int y, vector<vector<bool> > &visited) {
for (int minusrows = -1; minusrows < 2; minusrows++){ // going through the
// neighbouring cells (+ the cell itself)
for (int minuscolumns = -1; minuscolumns < 2; minuscolumns++){
if (x + minusrows > 0 && y + minuscolumns > 0 && x + minusrows < fogofwar.size() && y + minuscolumns < fogofwar[0].size()){ // checking
// if within borders
if (x > 0 && y > 0 && x < fogofwar.size() && y < fogofwar[0].size()) { // checking if the oririginal
// values are within borders
if (x > 0 && y > 0 && x < visited.size() && y < visited[0].size()) {
cout.flush();
}
visited[x][y] = true;
fogofwar[x + minusrows][y + minuscolumns] = to_string(display[x + minusrows][y + minuscolumns]); // revealing the
// neighbouring cells
if (display[x + minusrows][y + minuscolumns] == 0) { // if the cell is 0 on the display,
// open it and the 8 neighbouring to it cells
if (not visited[x + minusrows][y + minuscolumns]) { // if it's not the same cell, of course,
// otherwise it's an endless cycle
unravel(fogofwar, display, x + minusrows, y + minuscolumns, visited);
}
}
}
}
}
}
}
int main() {
int row, column, prob;
bool running = true;
cout << "Input width and height: ";
cin >> row >> column;
cout << endl << "Input mines probability (%): ";
cin >> prob;
cout << endl;
srand (time(NULL));
Int2D field(row + 1, Int1D(column + 1));
Int2D display(row + 1, Int1D(column + 1));
Str2D fogofwar(row + 1, Str1D(column + 1, "*"));
field[0][0] = 0; // field of mines
display[0][0] = 0; // display of neighbouring mines
fogofwar[0][0] = to_string(0); // what the player will see
for (int i = 1; i < row + 1; i++) { //assigning coordinates
field[i][0] = i;
display[i][0] = i;
fogofwar[i][0] = to_string(i);
}
for (int j = 1; j < column + 1; j++) { //assigning coordinates
field[0][j] = j;
display[0][j] = j;
fogofwar[0][j] = to_string(j);
}
for (int i = 1; i < row + 1; i++){ // filling the field with mines
for (int j = 1; j < column + 1; j++){
int x = rand() % 100;
if (x < prob) {
field[i][j] = 1;
}
else{
field[i][j] = 0;
}
}
}
cout << endl << endl;
for (int i = 0; i < row + 1; i++){ // printing field
for (int j = 0; j < column + 1; j++){
cout << " " << field[i][j] << " ";
}
cout << endl;
}
cout << endl << endl;
for (int i = 0; i < row + 1; i++){ // assigning the display of amount of neighbouring mines
for (int j = 0; j < column + 1; j++){
int count = 0;
if (i > 0 && j > 0){
for (int minusrows = -1; minusrows < 2; minusrows++){
for (int minuscolumns = -1; minuscolumns < 2; minuscolumns++){
if (i + minusrows > 0 && i + minusrows < row + 1 && j + minuscolumns > 0 && j + minuscolumns < column + 1){
if (field[i + minusrows][j + minuscolumns] == 1){
count++;
}
}
}
}
display[i][j] = count;
}
cout << " " << display[i][j] << " ";
}
cout << endl;
}
cout << endl << endl;
while (running) {
for (int i = 0; i < row + 1; i++){
for (int j = 0; j < column + 1; j++){
cout << " " << fogofwar[i][j] << " ";
}
cout << endl;
}
cout << endl;
int x, y;
cout << endl << "Input the target cell (x, y): ";
cin >> x >> y;
cout << endl;
vector<vector<bool> > visited(row+1, vector<bool>(column+1, false));
unravel(fogofwar, display, x, y, visited);
}
return 0;
}
The change is that I am maintaining a visited array, and I never go back to the spot I have already gone to before in unravel.