Rust: Checked Token Transfer

Rust

Never let a balance underflow.

Mariam Toure Sample Sep 17, 2026

Rust · 5 lines copied 39 times

fn transfer(from: &mut u64, to: &mut u64, amount: u64) -> Result<(), &'static str> {
    *from = from.checked_sub(amount).ok_or("insufficient balance")?;
    *to = to.checked_add(amount).ok_or("overflow")?;
    Ok(())
}

fn transfer(from: &mut u64, to: &mut u64, amount: u64) -> Result<(), &'static str> {
    *from = from.checked_sub(amount).ok_or("insufficient balance")?;
    *to = to.checked_add(amount).ok_or("overflow")?;
    Ok(())
}

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