What Is a Debugger and How Can It Help Me Diagnose Problems?
This Is Intended to Be a General-Purpose Question to Assist New Programmers Who Have a Problem with a Program, but Do Not Know How to Use a Debugger to...
This is intended to be a general-purpose question to assist new programmers who have a problem with a program, but do not know how to use a debugger to diagnose the cause of the problem.
This question covers three classes of more specific question:
- When I run my program, it does not produce the output I expect for the input I gave it.
- When I run my program, it crashes and gives me a stack trace. I have examined the stack trace, but I still do not know the cause of the problem because the stack trace does not provide me with enough information.
- When I run my program, it crashes because of a segmentation fault (SEGV).
2 Answers
A debugger is a program that can examine the state of your program while your program is running. The technical means it uses for doing this are not important for understanding the basics of how to use a debugger. You can use a debugger to halt the execution of your program when it reaches a particular place in your code, then examine the values of the variables in the program. You can use a debugger to run your program very slowly, one line of code at a time (called single stepping), while you examine the values of its variables.
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Using a debugger is an expected basic skill
A debugger is a very powerful tool for helping diagnose problems with programs. And debuggers are available for all practical programming languages. Therefore being able to use a debugger is considered a basic skill of any professional or enthusiast programmer. And using a debugger yourself is considered basic work you should do yourself before asking others for help. As this site is for professional and enthusiast programmers, and not a helpdesk or mentoring site, if you have a question about a problem with a specific program, but have not used a debugger, your question is very likely to be closed and downvoted. If you persist with questions like that, you will eventually be blocked from posting more.
Sarah Jenkins is a veteran tech journalist with over 12 years of experience covering artificial intelligence, mobile innovations, and digital ethics. Her insights have appeared in leading technology publications worldwide.
