# Integer Types

Fuzion knows signed and unsigned integer types in different sizes: u8, u16, u32, u64, u128 for unsigned values, i8, i16, i32, i64, i128 for signed values. Furthermore, int and uint can represent signed and unsigned integers of arbitrary size.

## 32-bit integers

Here is a small example calculating fibonacci numbers using 32-bit integers:

Due to the range limitations of type u32, this produces an error for n > 45.

## 64-bit integers

The possible range of values can be doubled using 64-bit integers:

Here, this produces an error for n > 91.

## 128-bit integers

Again, 128-bit integers double the number of fibonacci numbers we can generate, but this example only prints every 50th:

## Large integers

Type `int`

provides integers of an arbitrary size, but at the cost of reduced efficiency and higher memory demand:

## Integer as generic type

The abstract type `integer`

can be used to build a generic
function that works with integers of arbitrary sizes. The compiler will
specialize this code for the actual type that it is used with: