cvariables

Guarantateed minimum size/range of C data types

I have found varying answers to this question, and I know there must be one definitive answer. What is the minimum allocated memory size of the four main data types in C? int, double, float, and char are what I'm thinking of. Do the signed or unsigned types alter the size in any way?

Solution

  • You can use sizeof(variable):

    As an example running this on my local machine:

    sizeof (char)   = 1
sizeof (double) = 8
sizeof (float)  = 4
sizeof (int)    = 4
sizeof (long)   = 4
sizeof (long long)  = 8
sizeof (short)  = 2
sizeof (void *) = 4

    Note: the values you get may be determined by OS/Compiler/CPU architecture.