https://blog.zksecurity.xyz/posts/aleo-program-security/

example_program1.leo

program example_program1.aleo {
    mapping data_map: address => u8;
    
// transition is executed off-chain
    async transition save_sum(private a: u8, private b: u8) -> (u8, Future) {
        let sum: u8 = a + b;
        return (sum, finalize_save_sum(self.caller, sum));
    }
    
// finalize is executed on-chain
    async function finalize_save_sum(caller: address, sum: u8) {
        data_map.set(caller, sum);
    }
}

program example_program2.aleo {
    record Token {
        owner: address,
        amount: u128
    }
    transition private_transfer_token(private receiver: address, private token: Token) -> Token {
        let new_token: Token = Token {
            owner: receiver,
            amount: token.amount
        };
        return new_token;
    }
}