This example shows how to receive analog input and give output in wave form via the arduino our code will perform the following opertions.
Creates a array object consisting of all the pins.
Executing infinite loop for read and write continuously through the I/O pins.
In the loop, Take input into the zeroth analog pin.
Make the input value ready to be sent through a digital pin.
Give output from the 13th digital pin.
All these steps are implemented in just few lines of code