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What is a bug and why do we need to debug them?
As a programmer, you will inevitably come across bugs at some point. Despite the fact that you are well aware of this, you may not be able to fix bugs in a program unless you know how to find them. You wouldn’t understand why your friend can’t add two numbers if you hadn’t encountered the problem yourself. (For the record, his number is off by one.)
As a bonus, you will also learn how to debug your programs. A debug session is like a treasure hunt – you find bugs with clues given to you by the compiler. While it might not be exciting, it’s sure fun to feel that you are able to do a bit of detective work and locate errors in your program.
In this article, you will learn how to debug your programs. You’ll see how easy it is to find errors with a debug session at hand. You will also learn the debugging landscape, including debugging tools and techniques used by professional programmers.
What is a Bug?
How do you go about debugging a problem in your codebase?
In order to debug your code, you must first be able to recognize when a problem occurs. The best way of identifying bugs is through testing. You test your program by running it under different conditions. If you run the program a certain number of times and do not observe an error, it is likely that the bug does not exist in your program. However, if you don’t run the program often enough or if there are many errors, it is more likely that a bug exists. Most bugs can be traced to something not being coded properly. If you follow the code and fix the bugs, you will find that the code does what is expected of it. There are a few different ways to debug your code.
First, you can print out the value of any variables that may be causing a problem. Recall that in Java, all variables start with lower case letters and capitalize other words. If the program is saying that “NoneType” is defined by the object you are trying to set it to, it may have something to do with naming conventions. Try renaming it or changing its type from a String to an integer. After you have done this, try running the program again to see if it still gives an error. If it does not, then your problem was in the variable name and you should be able to move on.
What are some common techniques for tracking down bugs in software applications?
There are a number of different techniques for debugging software, including: * troubleshooting software * documenting bugs * writing test cases * re-testing * finding where the bug occurred * reproducing the bug * fixing the bug * QA testing (as well as user acceptance) * unit testing * regression testing * API testing * integration testing
Troubleshooting software
Other things related to trouble-shooting: * updating system drivers * expanding RAM or hard drive space (if it is a virtual machine) * checking to make sure that the OS or platform is supported by the software application (if applicable) * running an anti-virus scan of the computer for viruses, spyware, etc.
Documenting bugs:
Other considerations for bug documentation: * how to reproduce the bug under different conditions. * where is the bug occurring (on which software component or application)? * whether it happens on only a certain platform or operating system.
How to troubleshoot a DVD drive:
After you read this article, you will be able to troubleshoot one of your computer’s DVD drives if it fails to work properly.
How do you know when you’ve found the root cause of a bug and how do you fix it permanently?
The root cause of many bugs is in the code itself. You can find this root cause by tracing your program’s execution flow. With enough time and patience, it is possible to find every step that leads up to a bug’s occurrence. When you do so, however, you should first concentrate on finding the function that is most likely causing the bug. Fixing bugs this way allows you to fix the problem permanently by making updates throughout your codebase if necessary. Once the bug is fixed, there should be no more errors. Once you have correctly identified the root cause of the bug, you can fix it by making changes to your codebase. The old method for fixing bugs was to just make random changes in the hope that this would fix the problem. As you can imagine, this is not a very efficient way to fix bugs.
A better method is to use an instrumented application. The idea behind this approach is to change both your code and the instrumentation itself as little as possible. If a change in one area caused the error, you’d know that it required fixing in both areas. One such tool for JavaScript applications is Jserrorlog, which you can find at https://github.com/tonycubed2/JsErrorLog .
Are there any tools or methods that help make the process of debugging easier or faster?
This question refers to code that is used in compiling software. Code can be covered on a line-by-line basis, as well as over the course of an entire file. There is also code coverage tooling. You might also consider static analysis. Static analysis is a form of software verification. However, it does not look for bugs, but rather analyzes the structure and flow of programming code (the morphology). It can help you find potential problems before they occur in your program, so that the actual occurrence of bugs will be minor and isolated to individual source files. This can be a great tool for debugging and researching other software bugs!
Further, I’ve come across the great tool dbgrind which is used in conjunction with gdb. The idea behind dbgrind is that you can run the program under gdb’s control and monitor the program’s execution.
Several times I’ve run into memory leaks and segmentation faults, as well as other bugs such as incorrect API/ABI usage, race conditions and such. And I used gdb once, to help me with a segmentation fault.
This has been a very effective tool with overhead-free debugging and intense functionality that enables you to inspect both stack traces and heap memory at the same time.
