There are four signed integer types, and four unsigned integer types:
| Type | Length | Minimum Value | Maximum Value |
|---|---|---|---|
| Int8 | 8 | -128 | 127 |
| Int16 | 16 | −32,768 | 32,767 |
| Int32 | 32 | −2,147,483,648 | 2,147,483,647 |
| Int64 | 64 | −263 | 263 - 1 |
| UInt8 | 8 | 0 | 255 |
| UInt16 | 16 | 0 | 65,535 |
| UInt32 | 32 | 0 | 4,294,967,295 |
| UInt64 | 64 | 0 | 264 - 1 |
An integer literal is an optional + or - sign, followed by a sequence of digits and underscores, optionally followed by a suffix. If no suffix is present, the literal's type is the lowest between Int32, Int64 and UInt64 in which the number fits:
1 # Int32 1_i8 # Int8 1_i16 # Int16 1_i32 # Int32 1_i64 # Int64 1_u8 # UInt8 1_u16 # UInt16 1_u32 # UInt32 1_u64 # UInt64 +10 # Int32 -20 # Int32 2147483648 # Int64 9223372036854775808 # UInt64
The underscore _ before the suffix is optional.
Underscores can be used to make some numbers more readable:
1_000_000 # better than 1000000
Binary numbers start with 0b:
0b1101 # == 13
Octal numbers start with a 0o:
0o123 # == 83
Hexadecimal numbers start with 0x:
0xFE012D # == 16646445 0xfe012d # == 16646445
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https://crystal-lang.org/docs/syntax_and_semantics/literals/integers.html