stable and unstable sort....?

[siddharthmakwana]

what does stable and unstable sort means......?
what makes quick sort unstable and merge a stable one.....?(plz give example if possible...)

 

[the bot]

*mysmiley.net/imgs/smile/confused/confused0050.gif

 

[siddharthmakwana]

^^plz do not post ur facial expression after reading this thread......

 

[Liverpool_fan]

*en.wikipedia.org/wiki/Sorting_algorithm#Stability