Can someone explain this to me:

so basically it's supposed to return the absolute value of an integer. the absolute value is the value without any signs. So, basically the magnitude. since the magnitude of a negative number is just number itself( a double negative is positive). It returns positive if it's positive and negative of the negative number if it's negative.

If you understood everything in the explanation of Msaters, then all right. Else: make a sign to me and i will try to explain it in other words.

public mean u can use it everywhere in your program, everything has access to it static means that ur code will "load" it 1st to your program int abs(int a) {} - it is sort of function that will return int so some number bcs u have "int abs" if u would habe double abs u would have to return double value int abs(int a) - this "(int a)" means that while evocation this function u will have to put in there some int for example main{ int someInt; abs(someInt); } then u have how your function works it returns "-a" so value of int that u put there multiply -1 when value of a is less than 0 : iff(a < 0) return -a; else return a; if a is more than 0 u return a and that's all