Coin

Utility

0x45f248098da1...35a32baf504e

FrontierContract #4,200Exact Bytecode MatchEdit this contract

Deployed November 23, 2015 (10 years ago)Block 585,861

The Solidity tutorial subcurrency, a minter and a balance mapping

Frontier EraVerified Source

Context

Deployed in November 2015 on the Frontier chain. The subcurrency example was the first thing most people read after SimpleStorage, and it is the ancestor of the token contracts that followed.

Key Facts

Deployer

0x5b4dba...c82d52

Deployment Block

585,861

Deployment Date

Nov 23, 2015, 06:33 PM

Code Size

339.0 B

Gas at Deploy

123,489

Transactions by Year

20152

Deployment Transaction: 0xd04468b20e25fe5e...efce8145f28d6b7f

Description

The Coin example from the August 2015 Solidity Tutorial, deployed unchanged apart from the order its functions were written in. The account that deploys it becomes the minter and is the only one who may create units through mint. Holders move balances with send, which checks the sender's balance, adjusts both entries and emits a Send event carrying the sender, the receiver and the amount. queryBalance reads any address's balance. There is no total supply and no approval mechanism, so it predates the token interface that ERC-20 would later standardise.

Source Verified

Exact bytecode match(339 bytes)

Compiler: v0.1.1+

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Heuristic Analysis

The following characteristics were detected through bytecode analysis and may not be accurate.

Detected Type: Utility

Frontier Era

The initial release of Ethereum. A bare-bones implementation for technical users.

Block span: 0 — 1,149,999

July 30, 2015 — March 14, 2016

Bytecode Overview

Opcodes339

Unique Opcodes85

Jump Instructions20

Storage Operations11

Verified Source Available

Source verified through compiler archaeology and exact bytecode matching.

Verified on Etherscan

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Show source code (Solidity)

// Submitted by EthereumHistory (ethereumhistory.com)
contract Coin {
    address minter;
    mapping (address => uint) balances;
    event Send(address from, address to, uint value);

    function Coin() {
        minter = msg.sender;
    }
    function send(address receiver, uint amount) {
        if (balances[msg.sender] < amount) return;
        balances[msg.sender] -= amount;
        balances[receiver] += amount;
        Send(msg.sender, receiver, amount);
    }
    function mint(address owner, uint amount) {
        if (msg.sender != minter) return;
        balances[owner] += amount;
    }
    function queryBalance(address addr) constant returns (uint balance) {
        return balances[addr];
    }
}