Thread: how to troubleshoot core dumped (aborted) message

This program seemed to run fine the first time, but now it gives me a core dumped program aborted error which I do not understand why.
Here is the code:

Code:

#include <stdio.h>

int main ()
{
  int a[25], i, j, m, t;

  printf ("\nEnter 25 numbers \n");
  
  for (i=0; i<=24; i++)
  {

    scanf ("%d", &a[i]);

  }

  for (i=0; i<=24; i++)
    {

      for (j=0; j<=24-i; j++)
        {

          if (a[j] > a[j+1]) 
            {

               t=a[j];
               a[j]=a[j+1];
               a[j+1]=t;

            }

        }

    }
   printf ("\n  The sort list is \n");
   for (i=0; i<=24; i++)
      printf ("%d", a[i]);
}

In order to run the program, I created a data file contained 1 - 25 on each line and I would feed it to my executable as such:

./buble < data

I have attached the data file to the question. I tried to used gdb, but am not sure how to use redirection within gdb.

In the following line, what will the values of j and j+1 be when i is 0 and j reaches its maximum?

Code:

          if (a[j] > a[j+1])

In order to "troubleshoot" (not a bad word, but we usually say "debug") your program you can run it under a debugger such as gdb. gdb will show you the line that causes the segfault and you can examine the values of the variables at that point.

BTW, the common idiom in C is to write loops like this:

Code:

  for (i = 0; i < 25; i++)      // not i <= 24, although it amounts to the same thing

And it would be better to have a define for the size:

Code:

#define SIZE 25
...
  for (i = 0; i < SIZE; i++)
...