What Is The Type Of A Constant In C? - Jim Fisher

What is the type of a constant in C?

When we write expressions like this in C:

bool b = 1234567890 > 09876;

What are the types of those constants? The number 1234567890 - what is its type? How does C represent it when compiling it? The C Programming Language says:

An integer constant like 1234 is an int. A long constant is written with a terminal l (ell) or L, as in 123456789L; an integer constant too big to fit into an int will also be taken as a long. Unsigned constants are written with a terminal u or U, and the suffix ul or UL indicates unsigned long.

Floating-point constants contain a decimal point (123.4) or an exponent (1e-2) or both; their type is double, unless suffixed. The suffixes f or F indicate a float constant; l or L indicate a long double.

Here are some examples:

0 // int 0l // long 1234 // int 1234L // long 0ul // unsigned long 0u // unsigned int 2147483647 // int (just) 2147483648 // long 2147483647u // unsigned int 2147483648u // unsigned long (but could have fitted into an unsigned int) 0x0101010101010101ULL // unsigned long long Tagged #c, #programming, #semantics, #types.

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