oop - Java Increment / Decrement Operators - How they behave, what's the functionality?

Question

It's been 3 days since I start to learn Java. I have this program and I don't understand code in main method with ++ and -- operators. I don't even know what to call them(name of these operators) Can anyone explain me what's all about.

class Example {
    public static void main(String[] args) {
         x=0;
         x++;
         System.out.println(x);
         y=1;
         y--;
         System.out.println(y);
         z=3;
         ++z;
         System.out.println(z);
     }
}

Answer 1

These are called Pre and Post Increment / Decrement Operators.

x++;

is the same as x = x + 1;

x--;

is the same as x = x - 1;

Putting the operator before the variable ++x; means, first increment x by 1, and then use this new value of x

int x = 0; 
int z = ++x; // produce x is 1, z is 1


    int x = 0;
    int z = x++;  // produce x is 1, but z is 0 , 
                  //z gets the value of x and then x is incremented.