Introduction to Programming in C

📘 Debugging with GDB and Using Makefiles

As your programs grow in size and complexity, you'll need tools to debug errors and manage builds efficiently. In this chapter, you'll learn how to use GDB (GNU Debugger) for identifying bugs, and Makefiles for automating your compilation workflow.

🪲 What is GDB?

GDB is a command-line debugger for C/C++. It helps you inspect variables, step through code line by line, and trace logic errors.

🔧 Compiling with Debug Info

gcc -g program.c -o program

Use -g flag to include debug information.

📌 Common GDB Commands

• gdb ./program – Start debugger
• break main – Set a breakpoint at main()
• run – Start the program
• next – Execute next line
• print x – Print value of variable x
• backtrace – Show function call stack
• quit – Exit GDB

🧪 GDB Example

// buggy.c
#include <stdio.h>
int main() {
  int a = 5, b = 0;
  int result = a / b; // division by zero!
  printf("Result: %d", result);
  return 0;
}

Use GDB to step through the code and catch where it fails.

⚙️ Makefiles for Build Automation

A Makefile automates the compilation process — especially useful when your project has multiple files.

📝 Sample Makefile

all: main

main: main.o math.o
  gcc main.o math.o -o main

main.o: main.c
  gcc -c main.c

math.o: math.c
  gcc -c math.c

clean:
  rm *.o main

Run make to compile, and make clean to remove object files.

📚 UdaanPath Example

If UdaanPath’s C projects are split across files — e.g., UI logic in ui.c and backend logic in logic.c — a Makefile saves you from manually compiling each one.

✅ Summary

• GDB helps debug logic and runtime errors
• Breakpoints and step-through debugging are key features
• Makefiles simplify building multi-file projects
• Mastering these tools is essential for real-world development

🚀 Coming Next

Up next, we’ll cover Common C Interview Questions and Answers — prepare yourself for technical interviews with theory + code!