Increment and Decrement Operators

Like C and C++ , Java is also having the increment and decrement operators' i.e. ++ and --. Both  of these are unary operators.The operator + + adds 1 to the operand and - - subtract 1 from the operand.

They can be written in following from:
 x++  or x--
 ++x  or --x

Both forms of the ++ increment the value of variable by one i.e. x++ or ++x will be equivalent to x = x+1. As well as , x - - is equivalent to x = x - 1.

When the increment or decrement operator is used before variable,it is called as pre-increment or post-increment operator.And when it is used after variable.it is called as post-increment or post-decrement operator.

The difference is simple.That is, when these pre-increment or pre-decrement operators are involved in the arithmetic expression .
For example,
 z = 14;
 y = z ++;

Here, the value of variable y will be 14 and z will be 15, because in the second expression, post increment operator is used. Value of variable z is assigned to y first and then it is incremented.If we change the second expression to,
y = ++z;

Now, both the values of y and z will be 15.Pre-increment operator does its job first the then uses the value in the expression.