What is debugger?

A debugger is a special program that helps you look inside another program while it’s running. It lets you pause the program, see the values of variables, step through each line of code, and find out why something is going wrong.

Let's break it down

  • Run: Start the program inside the debugger.
  • Breakpoints: Mark spots in the code where the debugger will automatically pause.
  • Step: Move through the code line by line (step over, step into, step out).
  • Inspect: Look at variables, memory, and the call stack to see what the program is doing at that moment.
  • Modify: Change variable values on the fly to test different scenarios.
  • Continue: Let the program run again until the next breakpoint or the end.

Why does it matter?

Without a debugger, you would have to guess why a program crashes or behaves oddly, often by adding lots of print statements. Debuggers give you direct, real‑time insight, making it faster and easier to fix bugs, understand code flow, and improve program reliability.

Where is it used?

  • Software development: In IDEs like Visual Studio, IntelliJ, VS Code, Eclipse, etc.
  • Embedded systems: Using hardware debuggers to troubleshoot firmware on microcontrollers.
  • Web development: Browser developer tools (Chrome DevTools, Firefox Debugger) for JavaScript.
  • Mobile apps: Android Studio and Xcode debuggers for Android and iOS apps.
  • Education: Teaching programming concepts by visualizing execution.

Good things about it

  • Saves time by pinpointing the exact line causing a problem.
  • Reduces the need for messy logging or print statements.
  • Helps understand complex code paths and data flow.
  • Allows safe testing by changing values without recompiling.
  • Improves code quality and confidence in releases.

Not-so-good things

  • Learning curve: beginners may find breakpoints and stepping confusing at first.
  • Can be slower than running the program normally, especially with heavy applications.
  • Some bugs only appear in production environments and may be hard to reproduce in a debugger.
  • Over‑reliance on a debugger might limit practice in reading code and reasoning about logic.
  • Certain environments (e.g., highly optimized release builds) may limit debugging capabilities.