When would you use postfix vs the prefix ? Please show an example?

Answer 1

When you want something incremented/decremented before you use the variable, you must use prefixed operator, otherwise the variable will be used first and icremented after: e.g.

var i = 0;
var j = 0;

document.write(++i);
document.write(j++);

The values printed will be respectively 1 and 0.

The use of each other will vary accordingly with your necessity.

Answer 2

in simple way Suppose u have any variable like Int a=10;

and u want to use it start with 11 then u need preIncrement... it increments the value first then exicute..
int a =10;

system.out.println(++a);

output = 11