solana-program-examples/basics/processing-instructions/native/program/src/lib.rs

use borsh::{BorshDeserialize, BorshSerialize};
use solana_program::{
    account_info::AccountInfo, entrypoint, entrypoint::ProgramResult, msg, pubkey::Pubkey,
};

entrypoint!(process_instruction);

fn process_instruction(
    _program_id: &Pubkey,
    _accounts: &[AccountInfo],
    instruction_data: &[u8],
) -> ProgramResult {
    // Attempt to serialize the BPF format to our struct
    //  using Borsh
    //
    let instruction_data_object = InstructionData::try_from_slice(instruction_data)?;

    msg!("Welcome to the park, {}!", instruction_data_object.name);
    if instruction_data_object.height > 5 {
        msg!("You are tall enough to ride this ride. Congratulations.");
    } else {
        msg!("You are NOT tall enough to ride this ride. Sorry mate.");
    };

    Ok(())
}

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct InstructionData {
    name: String,
    height: u32,
}