Question

print ("not 30=", not 30)​

Answer 1

Answer:

When it evaluates what's inside the parentheses, it sees :

- a + b : the addition of two int (let's call it c)

- c + " " : an int and a String -> convert the int into a String and add the String's (let's call the result s)

- s + a : a String and an int -> same as before : converts the int into a String and add them together

- the last one (+b) works exactly the same way as the previous ones.  

A way to obtains 30 30 is  to write :

System.out.println(a + b + " " + (a + b));

By putting the second "a+b" in parentheses, we change the order of evaluation and this leads to adding them together before adding them to a String

Explanation: