Type of integer literals not int by default?

by

As far as C++ is concerned:

C++11, [lex.icon] ¶2

The type of an integer literal is the first of the corresponding list in Table 6 in which its value can be represented.

And Table 6, for literals without suffixes and decimal constants, gives:

int
long int
long long int

(interestingly, for hexadecimal or octal constants also unsigned types are allowed – but each one come after the corresponding signed one in the list)

So, it’s clear that in that case the constant has been interpreted as a long int (or long long int if long int was too 32 bit).

Notice that “too big literals” should result in a compilation error:

A program is ill-formed if one of its translation units contains an integer literal that cannot be represented by any of the allowed types.

(ibidem, ¶3)

which is promptly seen in this sample, that reminds us that ideone.com uses 32 bit compilers.

I saw now that the question was about C… well, it’s more or less the same:

C99, §6.4.4.1

The type of an integer constant is the first of the corresponding list in which its value can be represented.

list that is the same as in the C++ standard.

Addendum: both C99 and C++11 allow also the literals to be of “extended integer types” (i.e. other implementation-specific integer types) if everything else fails. (C++11, [lex.icon] ¶3; C99, §6.4.4.1 ¶5 after the table)

More Related Contents:

  1. Multicharacter literal in C and C++
  2. How do promotion rules work when the signedness on either side of a binary operator differ? [duplicate]
  3. (-2147483648> 0) returns true in C++?
  4. Why are string literals l-value while all other literals are r-value?
  5. How do I write a short literal in C++?
  6. Why does long long n = 2000*2000*2000*2000; overflow?
  7. Why is it allowed to pass R-Values by const reference but not by normal reference?
  8. Why are string literals const?
  9. Deprecated conversion from string literal to ‘char*’
  10. How to handle arbitrarily large integers
  11. Checking for underflow/overflow in C++?
  12. What is the datatype of string literal in C++?
  13. Should we generally use float literals for floats instead of the simpler double literals?
  14. comparison between string literal
  15. Is there a functional difference between “2.00” and “2.00f”?
  16. C++11 operator”” with double parameter
  17. What’s the C++ suffix for long double literals?
  18. When did C++ compilers start considering more than two hex digits in string literal character escapes?
  19. Why it is different between -2147483648 and (int)-2147483648
  20. What does LL mean?
  21. Assign a string literal to a char* [duplicate]
  22. Is it possible to have a pointer literal?
  23. Static array vs. dynamic array in C++
  24. How to make a SIMPLE C++ Makefile
  25. long long in C/C++
  26. What’s the right way to overload operator== for a class hierarchy?
  27. Inferring the call signature of a lambda or arbitrary callable for “make_function”
  28. Is the data in nested std::arrays guaranteed to be contiguous?
  29. constexpr const vs constexpr variables?
  30. Constexpr if alternative

Leave a Comment