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Ans - It depends. Rule - Whenever we try to access something, locals are checked first (afais-een). If enum value and variable are in same scope, then an error is guarantied. But they are in different scopes, then no (compiler) errors for this reason; but you may expect the unexpected behaviors; while coding you may think that you're trying to access a global variable or global enum value, it might have picked local enum value or variable with same name. To avoid this issue, enum are (most-ly 🤔) suffixed with _e in standard headers. Like in the case of datatypes being appended with _t.

Ans - No. Size of the data-type is yet not known so you can not do that, even if you try using typedef. GCC complains saying incomplete type.

Yes. But may not be achievable in single file. If an identifier is used, it must first be declared/defined earlier. That's not the case with typedef. A type can be aliased to another type even if the first type (that is being aliased) doesn't exist earlier. Compilation succeeds, except some kind of clarification may be needed to run the code. This usage yields opaqueness for a given type. And limits user to use the provided abstraction layer (typically getter, setter) and not the underlying data.

• Number of shifts for a number is negative ( a << -10)
• Number of shifts for a number is more than the bits in the number (sizeof(a) == 32 && a << 33)

Why do we need int8_t when we are sure that char consumes same size? Or for that matter why do we need stdint.h itself?

Ans - Till now char on C consumes 1B. But what about int? It varies across machines! So, if you definitely need 32b for your data, then pick uint8_t or int32_t instead of C's keyword based types. With this kind of usage, code change is not required across machines. So the purpose of these types is that, portability. And one more noticeable point is that, these words end with t; which simply means type or typedef.

• maintain a md table of format specifiers and corresponding data-types
• maintain a md table having operators and their precedence (include trigraphs with remarks)