run the simulator

I first got interested in arduino programming a long time ago.
I have been asked to write a programme recently and decided to get back into it.
I seem to remember being able to write a program in the arduino programmer and have it run a line at a time either slowly so it could be watched or stepping one line at a time by pressing a key on the keyboard? Am I correct and if so how is it done? or am I getting mixed up with another programmer?
Thanks,
Bob.

There is no such facility in the Arduino IDE so you must be getting confused with something else.

I have been searching what it could be I am mixing this up with? I also have a program called processing that is similar to the arduino one, I think I remember the arduino one is built using processing as a model, I’m not sure I explain that very well but I hope you get my drift?
I tried to load my arduino proramme into processing and it failed, it allowed me to copy and paste it in but errored when I ran it.
Is it possible to run a program written in the arduino programme in processing?

Is it possible to run a program written in the arduino programme in processing?

No. The programming languages are not the same. Processing is Java; Arduino is C++.