Counting Higher

The following fragment:

int count = 0;                  // statement 1

System.out.println( count ) ;   // statement 2
count = count + 1;              // statement 3

System.out.println( count ) ;   // statement 4

count = count + 1;               
System.out.println( count ) ;

will print out

0
1
2

The statement count = count + 1 increments the number in count. Sometimes programmers call this "incrementing a variable" although (of course) it is really the number in the variable that is incremented.

QUESTION 18:

What does the following assignment statement statement do:

sum = 2*sum ;

(What are the two steps, in order?)