Why sizeof(int) is not greater than -1? [duplicate]

Answer 1

Because sizeof(int) is unsigned. So -1 is converted to a large unsigned value.

Answer 2

Because sizeof yields a value of type size_t which is an unsigned type. In > expression usual arithmetic conversions will convert -1 to an unsigned type which is the type of the > result. The resulting value will be a huge positive value.

To get the expected behavior use:

(int) sizeof (int) > -1