where to find the Arduino source

I want to look into the source to find the code behind all the functions

for example i want to see how they accessed the ports with pinMode and analogRead etc....DDR..PORT...
and not just that , i want to look into many other things

I have looked into GitHub - arduino/Arduino: Arduino IDE 1.x but i dont even know where to look with all those different files.

They're all on your computer, assuming you downloaded the IDE.

If you download the Arduino software, it is all there.
You could search for "Wire.cpp" or "wiring_analog.c".

This is the standard software, https://github.com/arduino/Arduino/tree/master/hardware/arduino/cores/arduino
These are the standard libraries, https://github.com/arduino/Arduino/tree/master/libraries

The analog functions are in wiring_analog.c, https://github.com/arduino/Arduino/blob/master/hardware/arduino/cores/arduino/wiring_analog.c

good stuff guys .

Thanks.