set platformio to C++14

To set the platformio to C++14 in the C++ language, you need to follow these steps:

1. Open your project in the PlatformIO IDE or text editor of your choice.
2. Locate the platformio.ini file in the root directory of your project.
3. Open the platformio.ini file.
4. In the [env] section, add the following line: build_flags = -std=c++14
5. Save the platformio.ini file.

Explanation:

1. The platformio.ini file is a configuration file that contains settings for your PlatformIO project.
2. The [env] section in the platformio.ini file is where you can specify environment-specific settings for your project.
3. The build_flags option allows you to pass additional compiler flags to the build process.
4. -std=c++14 is the flag that tells the compiler to use the C++14 standard for compiling your code. C++14 is a version of the C++ programming language that was standardized in 2014 and introduced several new features and improvements over previous versions.
5. Saving the platformio.ini file ensures that the changes you made take effect.

By following these steps and adding the build_flags = -std=c++14 line in the [env] section of the platformio.ini file, you are instructing the PlatformIO build system to compile your C++ code using the C++14 standard.