Vector byte selection

Hi, i am trying to create a code that will allow me to select and store bytes into a vector.
I have a selection section that cycles through varies bytes of information with use of a track ball, this works fine, the problem occurs when i add the attachInterrupt() function, vectors and push.back. when i run the program and use the serial monitor, it displays 0. Is there another way of storing information or am i missing something basic? I have attached the code Im having problems with.

I have used for my vector(as a global variable) :

Vector Store;
byte AlphaNum;

void ButtonClickSelection(){
Store.push_back (AlphaNum);

void setup(){

attachInterrupt(digitalPinToInterrupt(2), ButtonClickSelection,LOW);

Post all you code not just a tiny fragment.

Please read this:-
How to use this forum
It will tell you how to post code here.

Somehow I think the code in your Original Post won't compile. Please post a complete program. And if you are using libraries that are not part of the Arduino IDE please provide links to where you got them.