IERC20Standard
ERC20 interface that includes the decimals read only method.
decimals() → uint8 external
Returns the number of decimals used to get its user representation.
For example, if decimals equals 2, a balance of 505 tokens should be displayed to a user as 5,05
(505 / 10 ** 2).
Tokens usually opt for a value of 18, imitating the relationship between Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is called.
| This information is only used for display purposes: it in no way affects any of the arithmetic of the contract, including {IERC20-balanceOf} and {IERC20-transfer}. |
transfer(address recipient, uint256 amount) → bool external
Moves amount tokens from the caller’s account to recipient.
Returns a boolean value indicating whether the operation succeeded.
Emits a {Transfer} event.
allowance(address owner, address spender) → uint256 external
Returns the remaining number of tokens that spender will be
allowed to spend on behalf of owner through {transferFrom}. This is
zero by default.
This value changes when {approve} or {transferFrom} are called.
approve(address spender, uint256 amount) → bool external
Sets amount as the allowance of spender over the caller’s tokens.
Returns a boolean value indicating whether the operation succeeded.
IMPORTANT: Beware that changing an allowance with this method brings the risk
that someone may use both the old and the new allowance by unfortunate
transaction ordering. One possible solution to mitigate this race
condition is to first reduce the spender’s allowance to 0 and set the
desired value afterwards:
https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
Emits an {Approval} event.
transferFrom(address sender, address recipient, uint256 amount) → bool external
Moves amount tokens from sender to recipient using the
allowance mechanism. amount is then deducted from the caller’s
allowance.
Returns a boolean value indicating whether the operation succeeded.
Emits a {Transfer} event.