Solana 中的几乎所有指令都需要至少 2 - 3 个帐户，并且它们
会在指令处理程序中提及，说明这些帐户集的预期顺序。如果我们利用iter() Rust 中的方法，而不是手动索引帐户，那么这相当简单。该 next_account_info方法基本上对可迭代对象的第一个索引进行切片，并返回帐户数组中存在的帐户。让我们看一个简单的指令，它需要一堆帐户并需要解析每个帐户。

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

entrypoint!(process_instruction);

#[derive(BorshSerialize, BorshDeserialize, Debug)]
pub struct HelloState {
    is_initialized: bool,
}

// Accounts required
/// 1. [signer] Payer
/// 2. [writable] Hello state account
/// 3. [] Rent account
/// 4. [] System Program
pub fn process_instruction(
    _program_id: &Pubkey,
    accounts: &[AccountInfo],
    _instruction_data: &[u8],
) -> ProgramResult {
    // Fetching all the accounts as a iterator (facilitating for loops and iterations)
    let accounts_iter = &mut accounts.iter();
    // Payer account
    let payer_account = next_account_info(accounts_iter)?;
    // Hello state account
    let hello_state_account = next_account_info(accounts_iter)?;
    // Rent account
    let rent_account = next_account_info(accounts_iter)?;
    // System Program
    let system_program = next_account_info(accounts_iter)?;

    Ok(())
}

https://solana.com/zh/developers/cookbook/programs/read-accounts