Compiling and Running C/C++ Code on Unix-like Systems

Introduction

Developing programs in C or C++ often involves writing code, compiling it to an executable, and then running that executable. This process is straightforward but requires some knowledge of the tools and environment settings specific to Unix-like operating systems such as Linux and macOS. In this tutorial, we’ll cover how to compile and run C/C++ programs using common command-line tools.

Prerequisites

Before beginning, ensure you have:

• A text editor (e.g., Vim, Nano, or VSCode) for writing your code.
• A Unix-like terminal (Terminal.app on macOS or any terminal in Linux).
• The GCC or G++ compiler installed. These are typically pre-installed on most systems.

Writing Your C/C++ Code

Create a simple C program named hello.c:

#include <stdio.h>

int main() {
    printf("Hello, World!\n");
    return 0;
}

Or a C++ program named hello.cpp:

#include <iostream>

int main() {
    std::cout << "Hello, World!" << std::endl;
    return 0;
}

Compiling the Code

Using GCC for C Programs

To compile a C program using the GNU Compiler Collection (GCC), use the gcc command:

gcc hello.c -o hello

Here:

• hello.c is your source file.
• -o hello specifies that the output executable should be named hello.

Using G++ for C++ Programs

To compile a C++ program, use the GNU C++ Compiler (g++):

g++ hello.cpp -o hello

This command works similarly to gcc, but it is used specifically for C++ source files.

Running the Compiled Program

Once compiled successfully, you can run your program. Navigate to the directory containing your executable and execute:

./hello

The ./ prefix specifies that the executable resides in the current working directory. This step is crucial because Unix-like systems do not search the current directory by default when looking for executables.

Automating with Make

For larger projects, manually compiling each file can become cumbersome. The make utility simplifies this process. If your project contains a single source file like foo.c, you can compile it directly using:

make foo

If no makefile is provided, make uses built-in rules to compile the program into an executable named after the source file (minus the extension).

Managing Executable Search Path

The Unix shell searches for executables in directories listed in the $PATH environment variable. To run your compiled programs without specifying their full path, you can add your directory to this list.

Displaying Current $PATH

Check your current $PATH with:

echo $PATH

Modifying $PATH

To include a custom directory (e.g., ~/bin) in your search path, edit or create the .bash_profile or .zshrc file in your home directory and add:

export PATH=~/bin:$PATH

This command prepends ~/bin to your existing $PATH, allowing executables in this directory to be run directly.

Conclusion

Compiling and running C/C++ programs on Unix-like systems is a straightforward process when you understand the tools available. By mastering these techniques, you can efficiently develop and execute your code across various platforms that support Unix-style environments.

Remember, practice is key—experiment with different commands and configurations to enhance your understanding of this essential development workflow.