The c_cpp_properties.json when developing for an Arduino Uno with the Arduino extension in the Visual Studio Code IDE.

c_cpp_properties.json (Arduino Uno)

{
    "configurations": [
        {
            "name": "Win32",
            "includePath": [
                "C:\\Program Files (x86)\\Arduino\\tools\\**",
                "C:\\Program Files (x86)\\Arduino\\hardware\\arduino\\avr\\cores\\**",
                "C:\\Program Files (x86)\\Arduino\\hardware\\arduino\\avr\\libraries\\**",
                "C:\\Program Files (x86)\\Arduino\\hardware\\arduino\\avr\\variants\\standard\\**"
            ],
            "forcedInclude": [
                "C:\\Program Files (x86)\\Arduino\\hardware\\arduino\\avr\\cores\\arduino\\Arduino.h"
            ],
            "intelliSenseMode": "gcc-x64",
            "defines": [
                "F_CPU=16000000L",
                "ARDUINO=10805",
                "ARDUINO_AVR_UNO",
                "ARDUINO_ARCH_AVR",
                "__AVR_ATmega328P__"
            ],
            "compilerPath": "C:\\Program Files (x86)\\Arduino\\hardware\\tools\\avr\\bin\\avr-gcc.exe"
        }
    ],
    "version": 4
}