Segmentation fault (core dumped)!

One of the most frustrating problems I’ve run in to date on my Water Drum game! Take a look at the output in the terminal:

alaskalinuxuser@alaskalinuxuser-OptiPlex-7010:~/Documents/c++/sfml_projects/sfml_water_drumming$ ./build.sh
DrumGame.cpp: In function ‘int main()’:
DrumGame.cpp:428:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if (roundNum == demoMode.length()) {
^
DrumGame.cpp:432:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
} else if (roundNum < demoMode.length()) {
^
DrumGame.cpp:506:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if (currentDemo == demoMode.length()) {
^
./build.sh: line 14: 3281 Segmentation fault (core dumped) ./DrumGame-app
type ./DrumGame-app to launch

A segmentation fault! But why?! It doesn’t really mention it here, so I tried to pull an strace on the program. Amongst pages and pages of gibbly-gook, there was this little gem about the exitButton being out of range.

DOH! I can be really, really, really dumb sometimes!

Here was my code:

window.draw(exitButton[numExitButtons].getSprite());

That should have been written as:

window.draw(exitButton[0].getSprite());

You see, there is only 1 exit button, so the numExitButtons variable was set to just 1. However, in an array (the []) the first (and only) exitButton starts with numeral zero! Boy, I can be a real dunce sometimes! All that time spent working on the issue that was a coder induced numerical error!

2018-06-12-124140_1280x1024_scrot

But, praise God, the DrumGame-app, Water Drumming! is complete! You can check the latest commits on GitLab, and download the source code as well! Be sure, once you extract it, to run the ./build.sh script. This game does require libsfml. If you try it out, you should drop a line to say what you think of it!

Linux – keep it simple.

2 thoughts on “Segmentation fault (core dumped)!

  1. Could you not just do: window.draw(exitButton[numExitButtons-1].getSprite());

    This is a classic off-by-one error. Thank you, computer scientists of the past. Everybody runs into this, so don’t beat yourself up about it.

    Liked by 1 person

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