What the purpose of code given with .PDE

Using Arduino Programming Questions
1

this question asked before, but never answered

.pde file can be opened on Arduino IDE

for beginners, why this file exists in examples
if not an Arduino sketch .ino to compile?
what its uses?

2

In:
http://www.reddit.com/r/arduino/comments/2v47hb/pde_vs_ino_and_define_vs_variable/

As far as I know, the .pde extension is used by the Processing IDE, which the Arduino IDE is based on.

3

Prior to IDE v1.00 the sketches were stored in a file with the extention .pde. With v1.00 it changed to .ino.

4

thank you, that make sense;

the language different,

  1. then would the code run on Arduino 1.6 IDE

for example a serial event function in code which not recognized?

  1. why we find such code now, or the code given if it will not work?

in other word, what the use for these code in this stage of Arduino?

5

The simple sketches should still compile ok but some of the .h files changed with IDE v1.00 too. If you try to compile one and you get errors then a brief search (top right hand corner of screen) will probably yield the answer.