Rust Error E0768: Non-decimal Number without Digits

Understanding Rust Error E0768

Rust Error E0768 occurs when you declare a number with a specified base, but you do not provide any digits. It is important to provide at least one digit when using non-decimal base notation to represent numbers in Rust.

Erroneous Code Example

```
#![allow(unused)]
fn main() {
    let n: i32 = 0b; // error!
}
```

In the code example above, we have a variable 'n' of the type i32 (32-bit signed integer). We attempt to use the binary (base-2) representation of the value by using the prefix '0b', but we do not provide any digits following the prefix. This results in Rust Error E0768.

Fixing Rust Error E0768

To fix Rust Error E0768, you must provide at least one digit following the non-decimal base prefix. The example below demonstrates how to correct the error by adding a binary digit after the '0b' prefix.

Corrected Code Example

```
#![allow(unused)]
fn main() {
    let n: i32 = 0b1; // ok!
}
```

In the corrected example, we have provided a binary digit '1' after the '0b' prefix. This resolves Rust Error E0768 and allows the code to compile successfully.

Non-decimal Number Bases

Rust supports the following non-decimal number bases: 1. Binary (Base-2): Prefix with '0b' 2. Octal (Base-8): Prefix with '0o' 3. Hexadecimal (Base-16): Prefix with '0x' When using any of these number bases, ensure that you provide at least one valid digit for the specified base following the prefix to avoid Rust Error E0768.