We already used a SD.h library in our previous chapter. By the term library, we usually mean collection of books or files. It can be a collection of anything. In programming, a library can be defined as the routines of precompiled code and programs. The routine may contain a number of necessary methods, classes, and other definitions. In a nutshell, a library is a collection of code written previously to be used when necessary. When you installed the Arduino IDE, a number of famous Arduino libraries had been installed to the Arduino directory. You can find them in the library folder. In my case, I found the following libraries installed when I installed Arduino IDE on my machine:
Adafruit_CircuitPlaygroundBridgeEsploraEthernetFirmataGSMKeyboardLiquidCrystalMouseRobot_ControlRobot_MotorRobotIRremoteSDServoSpacebrewYunStepperTembooTFTWiFi
In the Chapter 8, Working with Arduino Libraries, we will learn about a few famous libraries and their...