"Program received signal SIGSEGV, segmentation fault"

ben1996123 (31)
I've never had this problem with any of my other programs. I was making a Kenken solver, but I need a 3 dimensional array. I created the array and dynamically allocated the memory in main, but when I try to use the array in an if statement, I get this error. Here is some code that I'm using:

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#include <iostream>
#include <fstream>
using namespace std;

int gridsize;
int **grid;
int **zones;
char *operators;
int *totals;
int ***possibleValues;

int zoneCount();
void backtrack(int &aa, int &ab);
bool correct(int a, int b);
void printGrid();

int main(){
    ifstream file("k.txt");
    file >> gridsize;
    grid = new int *[gridsize];
    zones = new int *[gridsize];
    operators = new char [gridsize];
    totals = new int [gridsize];
    possibleValues = new int **[gridsize];
    for(int aa=0;aa<gridsize;aa++){
    	grid[aa] = new int [gridsize];
    	zones[aa] = new int [gridsize];
    	possibleValues[aa] = new int *[gridsize];
        for(int ab=0;ab<gridsize;ab++){
            possibleValues[aa][ab] = new int [gridsize];
        }
    }
    for(int aa=0;aa<gridsize;aa++){
        for(int ab=0;ab<gridsize;ab++){
            grid[aa][ab]=0;
            for(int ac=0;ac<gridsize;ac++){
                possibleValues[aa][ab][ac]=ac+1;
            }
        }
    }
        for(int aa=0;aa<gridsize;aa++){
		for(int ab=0;ab<gridsize;ab++){
			if(grid[aa][ab] == 0){
				for(int ac=1;ac<=gridsize;ac++){
					if(possibleValues[aa][ab][ac-1]!=0){
                                                //stuff
					}
				}
			}
		}
	}


I get the error on line 46.
slicedpan (155)
Hmm this code compiles and runs fine when i set gridsize to a constant, are you sure gridsize has a sensible value after you read it from the file?

EDIT:
also inside that loop, are you trying to access element possibleValues[aa][ab][ac]? That will segfault
Last edited on
ben1996123 (31)
Yes, gridsize is set to 6 when the program reads the file.
slicedpan (155)
Is this the exact code you are using? Can't reproduce the segfault.
ben1996123 (31)
I removed some other code that I thought was irrelevant to this error, but here's the full code up to the if statement:

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#include <iostream>
#include <fstream>
using namespace std;

int gridsize;
int **grid;
int **zones;
char *operators;
int *totals;
int ***possibleValues;

int zoneCount();
void backtrack(int &aa, int &ab);
bool correct(int a, int b);
void printGrid();

int main(){
    ifstream file("k.txt");
    file >> gridsize;
    grid = new int *[gridsize];
    zones = new int *[gridsize];
    operators = new char [gridsize];
    totals = new int [gridsize];
    possibleValues = new int **[gridsize];
    for(int aa=0;aa<gridsize;aa++){
        grid[aa] = new int [gridsize];
        zones[aa] = new int [gridsize];
        possibleValues[aa] = new int *[gridsize];
        for(int ab=0;ab<gridsize;ab++){
            possibleValues[aa][ab] = new int [gridsize];
        }
    }
    for(int aa=0;aa<gridsize;aa++){
        for(int ab=0;ab<gridsize;ab++){
            grid[aa][ab]=0;
            for(int ac=0;ac<gridsize;ac++){
                possibleValues[aa][ab][ac]=ac+1;
            }
        }
    }
    for(int aa=0;aa<gridsize;aa++){
        for(int ab=0;ab<gridsize;ab++){
            for(int ac=0;ac<gridsize;ac++){
                cout << possibleValues[aa][ab][ac] << " ";
            }
            cout << "\n";
        }
        cout << "\n\n";
    }

    for(int aa=0;aa<gridsize;aa++){
        for(int ab=0;ab<gridsize;ab++){
            file >> zones[aa][ab];
        }
    }
    for(int aa=0;aa<zoneCount();aa++){
        file >> operators[aa];
    }
    for(int aa=0;aa<zoneCount();aa++){
        file >> totals[aa];
    }
    cout << gridsize;
    for(int aa=0;aa<gridsize;aa++){
        for(int ab=0;ab<gridsize;ab++){
            if(grid[aa][ab] == 0){
                for(int ac=1;ac<=gridsize;ac++){
                    if(possibleValues[aa][ab][ac-1]!=0){
                        grid[aa][ab] = ac;
                        possibleValues[aa][ab][ac-1] = 0;
                        if(correct(aa, ab)){
                            break;
                        }
                        else if(ac == gridsize){
                            grid[aa][ab] = 0;
                            backtrack(aa, ab);
                        }
                    }
                }
            }
        }
    }
    return 0;
}
Last edited on
Peter87 (11254)
What does zoneCount() return?
ben1996123 (31)
14
Peter87 (11254)
In that case you have the problem on line 57 and 60. You try to access 14 elements when both arrays, operators and totals, only have size 6.
Last edited on
ben1996123 (31)
Ah thanks, didn't notice that. I fixed it now :)
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