Conditional compilation - Mini Project: Build & Apply

Using Conditional Compilation in C

📖 Scenario: You are writing a simple C program that behaves differently depending on whether it is compiled for debugging or for release. This is common in real-world software development to include extra information during development but keep the final program clean.

🎯 Goal: Build a C program that uses conditional compilation to print a debug message only when the DEBUG flag is defined.

📋 What You'll Learn

Create a macro called DEBUG to control debug messages

Use #ifdef DEBUG and #endif to conditionally compile debug code

Print a debug message only when DEBUG is defined

Print a normal message regardless of DEBUG

💡 Why This Matters

🌍 Real World

Conditional compilation is used in software development to include debug information or platform-specific code without changing the main source code.

💼 Career

Understanding conditional compilation is important for developers working on large projects, embedded systems, or cross-platform applications where different code runs in different environments.

1

Create the main function and print a normal message

Write a main function that prints "Program started" using printf.

C

int main() {
    // Your code here
}

Need a hint?

Remember to include stdio.h for printf.

2

Define the DEBUG macro

Add a macro definition #define DEBUG at the top of the program before main.

C

#include 

// Your code here

int main() {
    printf("Program started\n");
    return 0;
}

Need a hint?

Place #define DEBUG before the main function.

3

Add conditional compilation for debug message

Use #ifdef DEBUG and #endif inside main to print "Debug mode is ON" only when DEBUG is defined.

C

#include 

#define DEBUG

int main() {
    printf("Program started\n");
    // Your code here
    return 0;
}

Need a hint?

Put the debug printf between #ifdef DEBUG and #endif.

4

Print the final output

Run the program and print the output to show both messages when DEBUG is defined.

C

#include 

#define DEBUG

int main() {
    printf("Program started\n");
#ifdef DEBUG
    printf("Debug mode is ON\n");
#endif
    return 0;
}

// Your code here to print output

Need a hint?

Compile and run the program to see both messages printed.