What is an ERC20 token
The ERC20 token is the most commonly used token standard on the Ethereum blockchain. As such, it is the most popular token for companies running an ICO.
The ERC20 token required functions are:
- Get the total token supply:
function totalSupply() public constant returns (uint);
- Get the account balance of another account:
function balanceOf(address tokenOwner) public constant returns (uint balance);
- Returns the amount which the spender is still allowed to withdraw from the owner:
function allowance(address tokenOwner, address spender) public constant returns (uint remaining);
- Send amount of tokens to address:
function transfer(address to, uint tokens) public returns (bool success);
- Allow spender to withdraw from your account, multiple times, up to the amount written. If this function is called again it overwrites the current allowance with the value:
function approve(address spender, uint tokens) public returns (bool success);
- Send amount of tokens from one address to another address:
function transferFrom(address from, address to, uint tokens) public returns (bool success);
- Triggered when tokens are transferred
event Transfer(address indexed from, address indexed to, uint tokens);
- Triggered whenever approve is called:
event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}
Examples:
