Change basis from char to enum

[Naphann]

Currently, in the interface of qubit we refer to measurement basis using char. This can lead to hard to detect error when changing code. If the developer put a wrong char, it could be hard to debug.

Suggestion is to use enum instead of char.

quisp/quisp/backends/interfaces/IQubit.h

Lines 21 to 26 in d66ab32

	struct MeasurementOutcome {
	char basis;
	bool outcome_is_plus;
	char GOD_clean;
	bool operator==(const MeasurementOutcome &outcome) const { return basis == outcome.basis && outcome_is_plus == outcome.outcome_is_plus && GOD_clean == outcome.GOD_clean; }
	};

[MadhuMPandurangi]

hi @Naphann, I'm interested in working on this issue. can you please assign this to me? It'd help me with my academic evaluation too.
Thank You

[Naphann]

Hi @MadhuMPandurangi, sure! We would love to get some help.

[MadhuMPandurangi]

Thank you
I'll look into the documentation

[MadhuMPandurangi]

Hi can You @Naphann tell me the possible values that "basis" variable represents.

struct MeasurementOutcome {
  enum class Basis { X, Y, Z };
  Basis basis;
  bool outcome_is_plus;
  char GOD_clean;
  bool operator==(const MeasurementOutcome &outcome) const { return basis == outcome.basis && outcome_is_plus == outcome.outcome_is_plus && GOD_clean == outcome.GOD_clean; }
};

Thought of doing like the above code.
But I'm not getting the possible values that basis represent

Can you please help