🪴 Nishanth Gobi

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Create your own crypto token

May 15, 2024, 4 min read

A simple BEP-20 token

Solidity code

This contract represents a basic implementation of a BEP-20 token, which is a widely used standard for fungible tokens.

pragma solidity ^0.8.22; // Should be same as the version set in remix
 
contract Token {
 
    mapping(address => uint) public balances;
    mapping(address => mapping(address => uint)) public allowance;
 
    uint public totalSupply = 1000 * 10 ** 18; // Expressed in wei
    string public name = "hugo";
    string public symbol = "HUGO";
    uint public decimals = 18;
 
    event Transfer(address indexed from, address indexed to, uint value);
    event Approval(address indexed owner, address indexed spender, uint value);
 
    constructor() {
	    // Allocating all tokens to contract creator
        balances[msg.sender] = totalSupply;
    }
 
    function balanceOf(address owner) public view returns(uint) {
        return balances[owner];
    }
 
    function transfer(address to, uint value) public returns(bool) {
        require(balanceOf(msg.sender) >= value, 'Insufficient balance');
        balances[to] += value;
        balances[msg.sender] -= value;
        emit Transfer(msg.sender, to, value);
        return true;
    }
 
    function approve(address spender, uint value) public returns(bool) {
        allowance[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }
 
    function transferFrom(address from, address to, uint value) public returns(bool) {
        require(balanceOf(from) >= value, 'Insufficient balance');
        require(allowance[from][msg.sender] >= value, 'allownace too low');
        balances[to] += value;
        balances[from] -= value;
        emit Transfer(from, to, value);
        return true;
    }
}

Explanation

  1. Version Pragma:

    • pragma solidity ^0.8.22;: This line specifies the version of the Solidity compiler that should be used to compile the contract. The caret (^) symbol indicates that the contract should be compiled using a Solidity version greater than or equal to 0.8.22.

  2. Contract State Variables:

    • mapping(address => uint) public balances;: This mapping keeps track of the token balances for each Ethereum address. The balance of each address is represented as an unsigned integer.
    • mapping(address => mapping(address => uint)) public allowance;: This mapping is used to store allowances, allowing certain addresses to spend tokens on behalf of others.
    • uint public totalSupply = 1000 * 10 ** 18;: The total supply of the token, which is initially set to 1000 tokens. The value is expressed in wei, the smallest unit of Ether, by multiplying 10^18.
    • string public name = "hugo";: The name of the token.
    • string public symbol = "HUGO";: The symbol of the token (e.g., ETH for Ether or BTC for Bitcoin).
    • uint public decimals = 18;: The number of decimal places the token uses.

  3. Events:

    • event Transfer(address indexed from, address indexed to, uint value);: This event is emitted when tokens are transferred from one address to another.
    • event Approval(address indexed owner, address indexed spender, uint value);: This event is emitted when an address approves another address to spend tokens on its behalf.

  4. Constructor:

    • The constructor is executed only once when the contract is deployed. It initializes the balance of the contract creator (msg.sender) with the total supply of tokens.

  5. Public Functions:

    • balanceOf(address owner) public view returns(uint): Returns the balance of a specified address.
    • transfer(address to, uint value) public returns(bool): Allows an address to transfer a specified amount of tokens to another address. It checks for a sufficient balance and emits a Transfer event.
    • approve(address spender, uint value) public returns(bool): Allows an address to approve another address to spend a certain amount of tokens on its behalf. It updates the allowance mapping and emits an Approval event.
    • transferFrom(address from, address to, uint value) public returns(bool): Allows an address with an allowance to transfer tokens from the owner’s account to another address. It checks for sufficient balances and allowance, updates the balances, and emits a Transfer event.

Deployment

See the deployed coin at BSC scan Txn Hash: 0x8131bcd4527f0477874e83b78f3fc4b280341f1b2130c26e547b14eb31d1f878

Potential Issues

Refs

  1. https://www.youtube.com/watch?v=Q_wK6N9GtS8

Graph View