For STL professionals?

Hi specialists,

So here I bring some interesting interview exercises that has to be done in STL (IL). I've been working with S7-300 but to be honest, I would have some problems to do that in STL. Any of you ready to take a challenge? Making these in Java (in my place) wasn't so difficult, but I would be grateful for any solutions in STL, just for curiosity.

[FONT=&quot]Exercise 1[/FONT]
[FONT=&quot]Perform adding two numbers of type STRING and get result as STRING type[/FONT]


[FONT=&quot]Exercise 2[/FONT]
[FONT=&quot]Split a 3-digit number into 3 single numbers that will be placed in 3 consecutive bytes. Then perform reverse action and build a 3 digit number from three consecutive bytes.[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]Exercise 3[/FONT]
[FONT=&quot]Execute „circling 1” in one Word, but the place where you shift a bit is specified by POINTER[/FONT][FONT=&quot][/FONT]

Homework ?

Hints:

1. You can call other blocks in STL. Even blocks from the standard library.

2. BCD is your friend.

3. If you shift or rotate the bits in a word, then all bits are shifted/rotated not just one bit. So this one is unanswerable.