C++

For an assignment I need to have a program print the inputted number, and every number before it in sequence ex:

1
12
123
1234
12345
123456

I can get it to print a list of the number but for the love of god I cant get it to print the numbers before hand.  I know theres a simple way to do it nesting a while loop in a for loop but I can't fucking figure it out.

Help for a poor retarded aspiring programmer?

Can someone please tell me why all these people are printing the numbers from 1 to 6 as if the OP didn't specify the number has to be inputted and it's not always 6?

Also what IS the difference between List and Data.List?