Integers

An integer type is a range constrained field type. The Noir frontend currently supports unsigned, arbitrary-sized integer types.

An integer type is specified first with the letter u, indicating its unsigned nature, followed by its length in bits (e.g. 32). For example, a u32 variable can store a value in the range of $\\([0,2^{32}-1]\\)$:

fn main(x : Field, y : u32) {
    let z = x as u32 + y;
}

x, y and z are all private values in this example. However, x is a field while y and z are unsigned 32-bit integers. If y or z exceeds the range $\\([0,2^{32}-1]\\)$, proofs created will be rejected by the verifier.

Note: The default backend supports both even (e.g. u16, u48) and odd (e.g. u5, u3) sized integer types.