segmentation fault message

Both Niklas and Harish are correct. The former named the tool to narrow down where the error could be, the latter gives you a hunch what to look for once you've located a potentially problematic piece of code.

The error message you got may also be helpful in narrowing down the whereabouts of the error, but that is harder, and often not that helpful. And of course, you didn't yet tell us what it said.

What I usually do in such a case, is
1. look at the error
2. realize it isn't helping (most of the time)
3. Consider the steps I've performed that led to the error
4. Find a piece of code that I know has been executed shortly before the error occured
5. Set a breakpoint there
6. Run the program in debug mode, performing the same steps, until I hit the breakpoint
7. From there, step through the code until I trigger the instruction or function call that causes the error.
8.a) if a function call, and that functions code is not trivial, set a breakpoint here, and repeat from 6, this time making sure I step into that function rather than over it
8.b) else, repeat from 6, but stop right before the error occurs, and investigate the state of all variables, and see if the values are what I expect them to be
9. If after all this I still can't make heads or tails of this, ask someone else.

This all assumes that you know how to build a program in debug mode, and the error does occur in debug mode as well. If the latter isn't true, then it gets a lot harder (but more interesting too, IMHO ;) )

Check if you are trying to do any of the following:
-> dereferencing NULL,
-> dereferencing an uninitialized pointer,
-> dereferencing a pointer that has been freed (or deleted, ) or that has gone out of scope (in the case of arrays declared in functions),
-> writing off the end of an array.
-> recursive function that uses all of the stack space.