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Git Source Interface of the ERC20 standard as defined in the EIP.

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Functions

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totalSupply

Returns the amount of tokens in existence. 
function totalSupply() external view returns (uint256);

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balanceOf

Returns the amount of tokens owned by account. 
function balanceOf(address account) external view returns (uint256);

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transfer

Moves amount tokens from the caller’s account to to. Returns a boolean value indicating whether the operation succeeded. Emits a Transfer event. 
function transfer(address to, uint256 amount) external returns (bool);

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allowance

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 or are called. 
function allowance(address owner, address spender) external view returns (uint256);

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approve

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. 
function approve(address spender, uint256 amount) external returns (bool);

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transferFrom

Moves amount tokens from from to to 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. 
function transferFrom(address from, address to, uint256 amount) external returns (bool);

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decimals

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 default value returned by this function, unless it’s overridden. NOTE: 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}. 
function decimals() external view returns (uint8);

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Events

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Transfer

Emitted when value tokens are moved from one account (from) to another (to). Note that value may be zero. 
event Transfer(address indexed from, address indexed to, uint256 value);

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Approval

Emitted when the allowance of a spender for an owner is set by a call to approve. value is the new allowance. 
event Approval(address indexed owner, address indexed spender, uint256 value);