Introduction to Compiling Modern C++

The C++ programming language has undergone significant changes over the years, with new standards being released regularly. The most notable ones are C++11, C++14, C++17, and C++20. Each of these standards introduces new features, improves performance, and enhances the overall coding experience.

To take advantage of these modern C++ standards, you need to compile your code using a compatible compiler. In this tutorial, we will focus on compiling modern C++ code with g++, a popular C++ compiler.

Understanding Compiler Flags

Compiler flags are command-line arguments passed to the compiler executable to specify various options, such as the standard to use, optimization levels, and output file names. When compiling modern C++ code, you need to use specific flags to enable support for the desired standard.

The most common flag used with g++ is -std, which specifies the C++ standard to use. For example:

• -std=c++11 enables support for C++11 features.
• -std=c++14 enables support for C++14 features.
• -std=c++17 enables support for C++17 features.
• -std=c++20 enables support for C++20 features (note that not all features may be supported by the compiler).

Additionally, you can use the -std=gnu++XX flag to enable GNU extensions for a specific standard. For example:

• -std=gnu++11 enables support for C++11 features with GNU extensions.
• -std=gnu++14 enables support for C++14 features with GNU extensions.

Compiling Modern C++ Code

To compile modern C++ code using g++, follow these steps:

1. Open a terminal or command prompt.
2. Navigate to the directory containing your C++ source file (e.g., example.cpp).
3. Compile the code using the following command:

g++ -std=c++11 example.cpp -o example

    Replace `c++11` with the desired standard (e.g., `c++14`, `c++17`, or `c++20`).
4.  Run the compiled executable using the following command:
    ```bash
./example

Example Use Case: Compiling C++11 Code

Suppose you have a C++ source file called array_example.cpp that uses the <array> header, which is part of the C++11 standard:

#include <array>
#include <iostream>

int main() {
    std::array<int, 3> arr = {2, 3, 5};
    for (const auto& element : arr) {
        std::cout << element << " ";
    }
    return 0;
}

To compile this code using g++, you would use the following command:

g++ -std=c++11 array_example.cpp -o array_example

This will generate an executable file called array_example that you can run to see the output.

Checking Compiler Version and Support

If you encounter issues while compiling modern C++ code, it’s essential to check your compiler version and support for specific features. You can do this using the following commands:

• Check the compiler version:

g++ –version

*   Check the supported features:
    Refer to the [GCC C++ status page](https://gcc.gnu.org/projects/cxx-status.html) or the [cppreference.com compiler support page](https://en.cppreference.com/w/cpp/compiler_support).

Conclusion
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In conclusion, compiling modern C++ code with g++ requires using specific flags to enable support for the desired standard. By understanding compiler flags and checking your compiler version and support, you can ensure that your code takes advantage of the latest C++ features and improvements.