Sizeof string literal

sizeof returns the size in bytes of its operand. That should answer question number 1. ;) Also, a string literal is of type "array to n const char" when passed to sizeof.

Your test cases, one by one:

• "f" is a string literal consisting of two characters, the character f and the terminating NUL.
• foo is a pointer (edit: regardless of qualifiers), and pointers seem to be 4 bytes long on your system..
• For bar the case is the same as "f".

Hope that helps.

1. sizeof("f") must return 2, one for the 'f' and one for the terminating '\0'.
2. sizeof(foo) returns 4 on a 32-bit machine and 8 on a 64-bit machine because foo is a pointer.
3. sizeof(bar) returns 2 because bar is an array of two characters, the 'b' and the terminating '\0'.

The string literal has the type 'array of size N of const char' where N includes the terminal null.

Remember, arrays do not decay to pointers when passed to sizeof.