when you write numerical value starting with '0x', It will be recognized as hexadecimal.
int hex=0xA;//It is same as 10. whether capital letter or small letter,it is ok.
what is Hexadecimal?
Hexadecimal number is that when it comes to 16,then go up to next digit.
range is from 0 to 16.
In programming, over ten number is represented as alphabets(a-f).
What is use for?
In hexadecimal , 4bit set is one character.
this is useful when you think of binary numeral system.