E. What would the code segment in Listing 4 output? [15 points] Listing 4: Code Segment 1

# include < iostream >

using namespace std ; 4

void enigma (int & a , int & b , int c)

{

7 cout <<<" "<<<" "<<< endl ;

a = a + b;

b = a - b;

a = a - b;

c = a - b;

cout <<<" "<<<" "<<< endl ;

}

int main ()

{

int a =1 , b =2 , c =3;

cout <<<" "<<<" "<<< endl ;

enigma (c ,a , b);

cout <<<" "<<<" "<<< endl ;

return 0;

}

I know the outputs are:

123

312

13 -2

321

I dont understand how the 4th line is derived. My professor just kind of skipped over that.