# Hello Bitcoin!

By [Soul](https://paragraph.com/@soul-2) · 2021-10-15

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Hello Bitcoin！😊

    // Copyright (c) 2009-2010 Satoshi Nakamoto
    // Copyright (c) 2009-2018 The Bitcoin Core developers
    // Distributed under the MIT software license, see the accompanying
    // file COPYING or http://www.opensource.org/licenses/mit-license.php.
    
    #ifndef BITCOIN_CONSENSUS_AMOUNT_H
    #define BITCOIN_CONSENSUS_AMOUNT_H
    
    #include <cstdint>
    
    /** Amount in satoshis (Can be negative) */
    typedef int64_t CAmount;
    
    static constexpr CAmount COIN = 100000000;
    
    /** No amount larger than this (in satoshi) is valid.
     *
     * Note that this constant is *not* the total money supply, which in Bitcoin
     * currently happens to be less than 21,000,000 BTC for various reasons, but
     * rather a sanity check. As this sanity check is used by consensus-critical
     * validation code, the exact value of the MAX_MONEY constant is consensus
     * critical; in unusual circumstances like a(nother) overflow bug that allowed
     * for the creation of coins out of thin air modification could lead to a fork.
     * */
    static constexpr CAmount MAX_MONEY = 21000000 * COIN;
    inline bool MoneyRange(const CAmount& nValue) { return (nValue >= 0 && nValue <= MAX_MONEY); }
    
    #endif //  BITCOIN_CONSENSUS_AMOUNT_H

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*Originally published on [Soul](https://paragraph.com/@soul-2/hello-bitcoin)*