Sorting -- Capital letters come first than small letters

You should typically uses a localized sort when displaying data to the user.

Normally in a sort, capitalization don't matters except when a string only differ in capitalisation.

I would think that in most language capital letter come first.

Thus, the typically sorted output should be:

AA
aa
Ab
bb

C++ has locale for that... but I never used them. I was generally using Windows sort functions

lstrcmp Function (Win32 API)[^]

When the sorting is used for display purpose, sort should typically be done according to text language (or OS language). When sort is only used internally, default sort might be appropriate.

The expected output definitely calls for a custom sorting routine.
You could use the std::sort function with a user defined predicate function that puts all lower case before upper case.
The ASCII table posted by Richard is a must know.

I got the solution, i tried to use std::sort etc etc, i don't have much knowledge on it.

So when comparing the string in the end compare function, i am reversing the input text in the end function, i am changing small letters to caps and caps to small letters, this is a workaround for now but its giving me the results i want.