int8 int16 int32 int64
uint8 uint16 uint32 uint64
int uint : natural and most efficient size on a particular platform. Different compiler may choose different size. Don’t use int when int32 is needed.
Type rune is a synonym for int32, indicate value is a unicode point
Type byte is a synonym for int8
Type uintptr is an unsined integer, width is not specified, used to hold a pointer value. For low level programming with C library.
High-order is reserved for the sign of the number.
Operator % applies only to integers
Results of -5%3 and -5%-3 are both -2
Result of 5.0/4.0 = 1.25
Result of 5/4 = 1, it's treated as integer