can I get an explanation about this section of the smart contract especially the supply function. and what does

 totalSupply = _supply * 10**_decimals;

means? I will like to created a mintable token with maximum supply capped

contract CoinToken is PausableToken {
string public name;
string public symbol;
uint public decimals;
uint public supply_cap;
event Mint(address indexed from, address indexed to, uint256 value);
event Burn(address indexed burner, uint256 value);

constructor(string memory _name, string memory _symbol, uint256 _decimals, uint256 _supply, address tokenOwner) public {
    name = _name;
    symbol = _symbol;
    decimals = _decimals;
    totalSupply = _supply * 10**_decimals;
    balances[tokenOwner] = totalSupply;
    owner = tokenOwner;
    emit Transfer(address(0), tokenOwner, totalSupply);

function burn(uint256 _value) public {
    _burn(msg.sender, _value);

function _burn(address _who, uint256 _value) internal {
    require(_value <= balances[_who]);
    balances[_who] = balances[_who].sub(_value);
    totalSupply = totalSupply.sub(_value);
    emit Burn(_who, _value);
    emit Transfer(_who, address(0), _value);

function mint(address account, uint256 amount) onlyOwner public {

    totalSupply = totalSupply.add(amount);
    balances[account] = balances[account].add(amount);
    emit Mint(address(0), account, amount);
    emit Transfer(address(0), account, amount);

1 Answer 1


The totalSupply saves the supply taking the decimals into account. The ** operator means power to the following number, is like saying 10^_decimals.

Lets say you have a _supply = 1 with _decimals = 0, the total supply would be 1 * 10^0 = 1*1 = 1.

That would mean that if you mint 1 means 1 tokens.

There is no getting lost with that, but let's say we support 2 decimals:

_supply = 1;
_decimals = 2;
totalSupply = 1*(10^2);
totalSupply = 100;

That would mean that if you mint 50 means 0.5 tokens. Or if you mint 100 its 1 token.

  • Thanks Julissa, that means, if I created a token with decimal as 2, i can have 0.01 as the minimum right?
    – Csmart
    Feb 7, 2022 at 20:57

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