Getting an error: "Segmentation fault (Core Dumped)" on my program. Everything working otherwise. Why?

Question

I'm getting an error "segmentation fault(core dumped)" for my program here, but everything in the program seems to be working fine. I understand what the error signifies I just cant identify what in my code is causing it. Any ideas?

#include <cmath> // for use of math functions
#include <iomanip> // for output display
#include "cosc1437_tk_1371133.h"
using namespace std;

//Global Constansts
const int ROWS = 3;
const int COLS = 10;

//Prototypes: None (other than defined in toolkit)

// MAIN program
int main()
{

  // Hello Message
  displayMessage("Hello. This program will demonstrate the use of 2D Arrays and mathematical operations.");

  // Intialize and load arrays with flight information
  int dArr[ROWS][COLS];

  for (int i = 2; i < ROWS + 2; i++){
    for (int j = 1; j < COLS + 1; j++) {
      dArr[i][j] = pow(i, j);
      cout << setw(8);
      cout << dArr[i][j];
    }
    cout << "\n";
  }

  //Goodbye Message
  displayMessage("Goodbye!");
}

*"I just cant identify what in my code is causing it"* - are you sure that iterating from `2` to `ROWS + 2` on array that has `ROWS` elements is a good idea? — Yksisarvinen, Jul 20 '21 at 15:33
Umm, because you are accessing elements out of range: `dArr[i][j] = pow(i, j);` ? — pptaszni, Jul 20 '21 at 15:33
Using all uppercase for constants is a bad habit and antipattern in C++ — Slava, Jul 20 '21 at 15:44

score -1 · Answer 1 · answered Jul 20 '21 at 15:42

for (int i = 2; i < ROWS + 2; i++){
    for (int j = 1; j < COLS + 1; j++) {
          dArr[i][j] = pow(i, j);

You set the max value of ‘i’ and ‘j’ to exceed ROWS and COLS, which you used to set the array dimension with.

Since max position in the array is 1 less than the value used:

int a[9]; // indexes 0 through 8.

So when you attempt to access a position of ROWS or COLS you exceed the array’s size. This translates into a segfault.

Getting an error: "Segmentation fault (Core Dumped)" on my program. Everything working otherwise. Why?

1 Answers1