Mastering Blockchain - Second Edition

Integers

This data type represents integers. The following table shows various keywords used to declare integer data types:

Keyword	Types	Details
int	Signed integer	int8 to int256, which means that keywords are available from int8 up to int256 in increments of 8, for example, int8, int16, int24.
uint	Unsigned integer	uint8, uint16, ... to uint256, unsigned integer from 8 bits to 256 bits. The usage is dependent on the requirements that how many bits are required to be stored in the variable.

For example, in this code, note that uint is an alias for uint256:

uint256 x;  
uint y;  
uint256 z; 

These types can also be declared with the constant keyword, which means that no storage slot will be reserved by the compiler ...