Smallest data type - can I define a one bit variable? [duplicate]

Question

I need only one bit to represent my data - 1 or 0. What is the best way to do so in C? The "normal" data types are too large.

Answer 1

You could create

typedef struct foo {     unsigned x:1; } foo; 

Where you have told the compiler that you'll only be using one bit of x.

But due to structure packing arrangements (the C standard is intentionally flexible in order that compilers can optimise according to the machine architecture), it may well turn out that this still occupies as much space in memory as a regular unsigned and an array of foos doesn't have to be bitwise contiguous.

Answer 2

If you really want, you can create a structure with a member variable , bit-fielded to 1 bit.

Remember, the data type of the member variable needs to be unsigned, as you need to store 0 and 1.