I don't understand the postfix thing

Answer 1

In postfix the operator comes after the operand. This form follows the Use-then-Change rule i.e it evaluates the value of the operand before the increment/decrement operation.

for eg: sum = sum + op++ ;

here it increments op by 1; evalutes to the value of op BEFORE it was incremented.

but when it comes to prefix the situation is reversed, it uses Change-then-use rule...

instead of op++ it uses ++op

where it increments op by 1 BUT evalutes to the value of op AFTER it was incremented.

Hope it was helpful.....

Answer 2

prefix means : ++x
it shows that the value of x will be first incresed by 1 and then saved it in x.
and anotherone is postfix means : x++
it shows that if we use the statement of print as like:
system.out.print(x++);
it's print current value of x and then the after the value is increased by 1.