I don't see how this answers the question. The question is, how can a string represent a C++ program? I don't see that this answers that question. It does not describe a way that a string can represent a C++ program.
The question is more accurately described as:
"how can a string represent a C++ program"
[so that halt decider h can examine the function f] ?
I cited an academic paper in the field of termination analysis that suggested
low-level intermediate languages that occur during the compilation of C programs to machine code have a much simpler semantics since most of the intricacies of C are taken care of by the compiler frontend.
Then I provided a concrete example of examining the halt status of the code sample provided in the question using a simulating halt decider to analyze the execution trace of the machine language of this code sample.
(1) In the following there is a link to the original question.
(2) The body of my revised answer that was rejected by the moderator.
(3) The original moderator comment that was addressed by my revision.
The question is more accurately described as:
"how can a string represent a C++ program"
[so that halt decider h can examine the function f] ?