Inserted 6 integers, list y should be 1 2 3 4 5 6
Size of y = 6
Ouput using forward iterators pre and post ++
1  2  3  4  5  6  
1  2  3  4  5  6  
Incremented by 1 list is 2  3  4  5  6  7  
The sum of the elements is 27
Appended 3 integers, list y should be 1 2 3
Size of y = 3
1  2  3  
List y should be 0 1 2 3 4
Size of y = 5
0  1  2  3  4  
List y should be 1 2 3 6
Size of y = 4
1  2  3  6